Distribution and its mechanisms of Branchinecta gaini (Branchiopoda: Anostraca) in the area of the Wilhelm Archipelago (Maritime Antarctica)

Distribution and its mechanisms of Branchinecta gaini (Branchiopoda: Anostraca) in the area of the Wilhelm Archipelago (Maritime Antarctica) | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Distribution and its mechanisms of Branchinecta gaini (Branchiopoda: Anostraca) in the area of the Wilhelm Archipelago (Maritime Antarctica) Vladlen Trokhymets, Ihor Dykyy, Artem Zinkovskyi, Patricio R. De los Rios-Escalante This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6255807/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The anostracan Branchinecta gaini is the largest animal, the main consumer of detritus and benthos, and a background species of energy harvester in the trophic food chains of Antarctic freshwater bodies. This crustacean species was first recorded in the freshwater reservoir of Petermann Island (Wilhelm Archipelago, Maritime Antarctica) during the Second French Antarctic Expedition of Jean-Baptiste Charcot in 1909. This work aimed to investigate the current distribution and its mechanisms of B. gaini in the Argentine Islands of this archipelago. Branchinecta gaini was found during our research within the freshwater bodies of Uruguay and Galindez Islands in 2007. In addition, this species was registered in reservoirs of three islands in 2008, six islands in 2010, and nine islands in 2020. As a result, B. gaini was found in the 32 freshwater bodies of 12 islands in the Wilhelm Archipelago region and for the first time in reservoirs of 11 islands. Different ways and mechanisms of the distribution of B. gaini in extreme Antarctic conditions were also considered. Zoogeography Branchiopods Freshwater crustaceans Antarctic Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Introduction Antarctica is characterized by unique and extreme conditions for the existence of living organisms. They are especially complex within terrestrial ecosystems (Convey 2017 ). This is due to the fact that daily and seasonal fluctuations in indicators of various environmental factors (for example, temperature) within terrestrial ecosystems are high. Instead, these indicators are more stable in the marine environment of the Antarctic. Therefore, the biota of terrestrial ecosystems should be characterized by high physiological and ecological flexibility in relation to changes in environmental factors (Peck 2005 ). Aboriginal biota has adapted to exist in such harsh conditions over millions of years. However, modern changes in the environment caused by high rates of warming can lead to an increase in the size of species areal, quantitative indicators of populations, productivity, complexity of communities, as well as the penetration of new species into the Antarctic territory (Convey and Peck 2019 ; Bargagli 2020 ). A special place in terrestrial ecosystems is occupied by permanent and temporary freshwater reservoirs (lakes, ponds, rock pools). The most quantitatively represented are small water bodies, among which rock pools predominate (Hawes et al. 2011 ). The latter are among the oldest and most extreme temporary habitats (Brendonck and Riddoch 1999 ). The biota of these freshwater bodies on the territory of different continents includes about 460 species of animals. Antarctic rock pools are characterized by the highest rates of species diversity of fauna compared to other continents, which is associated with the development of specific adaptations to extreme habitat conditions. Antarctic animals with the strategy of active dispersers are represented by 42 genera, and with the strategy of passive dispersers – 41 genera. For comparison, animals with corresponding strategies are represented in rock pools of North America by 32 and 14 genera (Jocqué et al. 2010 ). The basis of biodiversity and biomass of different taxonomic groups of Antarctic freshwater bodies’ biota is formed by cyanobacteria and plants, and their stability is determined by animals. Benthos and plankton predominate in the life forms to which representatives of various taxonomic groups may belong. The benthos forms the basis of the biodiversity and biomass of freshwater bodies, and the plankton provides their stability (Gibson et al. 2006 ). In total, 336 taxa (defined to species, genera, and higher-level taxa) of invertebrate animals have been registered in various types of Antarctic freshwater bodies. Of these, 121 taxa are known for the waters of Maritime Antarctica (Dartnall 2017 ). Crustaceans play an important role as first- and second-order consumers (Pugh et al. 2002 ). They are represented by 66 taxa, nine of which were found in the Maritime Antarctic. Just four species of crustaceans have been registered in freshwater bodies of the Antarctic Peninsula: two species of branchiopods and two copepods (Diaz et al. 2019; Trokhymets et al. 2021 ). Today, about 500 species belong to the Class Branchiopoda Latreille, 1817. Several taxonomic groups are distinguished within the class: fairy shrimps (Order Anostraca Sars, 1867), clam shrimps and cladocerans (Superorder Diplostraca Latreille, 1829), and tadpole shrimps (Order Notostraca Sars, 1867). Anostracans live mainly in temporary freshwater bodies, although marine species are also found among them. The vast majority of these crustaceans belong to omnivorous filter feeders, although predators are also found among them (Brendonck et al. 2008 ). Adverse conditions are tolerated by the formation of resting egg ("cysts") banks in the water (Brendonck 1996 ). Anostracans are large branchiopods, but in recent decades many new species have been described within different regions of the planet (Rogers and Ferreira 2007 ; Lazo-Wasem and Hegna 2010 ). Thus, these crustaceans numbered 258 species in 1993 (Belk and Brtek 1995 ), and they numbered about 300 species already in 2008 (Brendonck et al. 2008 ). This can be explained by the fact that almost 25% of these species are known only from typical localities (Belk and Brtek 1995 ). Branchinecta Verrill 1869 from the family Branchinectidae Daday, 1910 is the only genus of anostracans whose representatives live in Antarctic freshwater bodies. This genus includes about 48 species, distributed in water bodies on most continents except Africa and Australia (Evtimova et al. 2024 ; Rogers et al., 2020b ). Antarctic Fairy Shrimp ( Branchinecta gaini Daday, 1910) is the only anostracan species present in Antarctic freshwater bodies (Rosenfeld et al. 2023 ). For the first time, this species was found on Petermann Island (65°10°34"S 66°32'30"W) and small islands located near it in the area of ​​the Wilhelm Archipelago (Maritime Antarctica) during the Second French Antarctic Expedition with led of Jean-Baptiste Charcot by Mr. L. Hein in 1909 (Dabay De Deés 1910). Until recently, representatives of this species were believed to be widespread in freshwater bodies of southern South America (De Los Rios et al. 2008; Rogers et al. 2008 ; De Los Ríos-Escalante and Kotov 2015 ), Falkland Islands (Weller 1975 ; Hawes 2009 ; Diaz et al. 2019), South Georgia (Dartnall and Heywood 1980 ; Dartnall 2005 ; Dartnall 2017 ), South Orkney Islands (Brendonck et al. 2008 ; Dartnall 2017 ; Diaz et al. 2019), South Shetland Islands (Janiec 1996 ; Toro et al. 2006 ; Rochera and Camacho 2019 ), and Antarctic Peninsula (Björck et al. 1996 ; Hawes 2008 ; Nedbalova et al. 2017). According to this approach, B. gaini coexisted in Patagonia with the very morphologically similar species Branchinecta granulosa Daday, 1902 (Linder 1941 ; Rogers et al. 2008 ). In addition, a number of sources noted records of B. granulosa in freshwater bodies of the Antarctic (Bryant 1945 ; Polishuk et al. 2009 ). However, most scientists disputed this possibility and believed that these were misidentifications of B. gaini (Pugh et al. 2002 ; Hawes 2009 ; Rogers et al. 2020a ). The existence of B. gaini in southern South America and the Falkland Islands has long been questioned (Pugh et al. 2002 ; Rogers et al. 2020a ). Shortly after, Rogers et al. ( 2020b ) concluded that all Patagonian finds of B. gaini actually belong to B. granulosa and that the distribution of B. gaini is restricted to Antarctica and adjacent islands. Comparative molecular genetics and phylogenetic analyzes of B. granulosa and B. gaini were carried out in 2024. The analysis revealed insufficient genetic differentiation between the two species, suggesting the existence of a single species with small morphological differences between its populations within different areas of its areal (Pokorný et al. 2024 ). Therefore, there are two main approaches to the distribution of B. gaini , based on the modern revision within the genus Branchinecta : 1) B. granulosa and B. gaini are separate species, the areal of the first is limited to South America, and the second to Antarctica and adjacent islands (the population of B. gaini from the Falkland Islands need additional analysis); 2) B. granulosa and B. gaini are the same species. In our publication, we will adhere to the more generally accepted first approach (Fig. 1 ), but note the need for further study this question. As for research on B. gaini in the area of ​​the Wilhelm Archipelago, in addition to the first finding of this species by Mr. L. Hein in 1909 (Dabay De Deés 1910), studies are fragmentary. They are represented mainly by references to this species by English and Ukrainian researchers, unpublished scientific reports and several publications (Polishuk et al. 2009 ; Chernov et al. 2020 ). This species was described as B. granulosa , and the findings were mainly presented with information about the discovery of this species within several islands (Galindez, Skua, Mitina, and Uruguay Islands) without coordinates or reference to freshwater bodies. This species was later redefined as B. gaini (Chernov et al. 2021 ; Trokhymets and Dykyy 2021 ). Our article aimed to study the distribution and its mechanisms in freshwater anostracan crustacean B. gaini in region of ​​the Wilhelm Archipelago. Materials and methods Place and date of material collection Samples were collected in freshwater bodies in the region of the Wilhelm Archipelago. We used the next classification of freshwater bodies (Trokhymets et al. 2024 ): 1) “Lake” not freeze to the bottom, the depth is more than 2 m, and the area is 100 m 2 and more; 2) “Pond” freezes to the bottom in winter, their depth is less 2 m, and the area is from 10 to 100 m 2 or more with low depth; 3) “Rock pool” freezes to the bottom in winter, their the depth not exceed 1 m, and the area is less 10 m 2 . The samples were collected during the wintering of the 12th Ukrainian Antarctic Expeditions in March 2007, the wintering of the 12th Ukrainian Antarctic Expeditions in January-February 2008, the wintering of the 14th Ukrainian Antarctic Expeditions in January-March 2010, and the season of the 25th Ukrainian Antarctic Expedition in February-April 2020. A total of eight samples were taken in freshwater bodies of four islands and the Cape Rasmussen in 2007, seven samples on six islands in 2008, 18 samples on 12 islands and the Cape Rasmussen in 2010, and 111 samples on 20 islands and three continental capes in 2020. Table 1 presents those freshwater bodies with their geolocation using GPS where B. gaini was found. Table 2 presents those reservoirs where B. gaini was absent. Table 1 Records of Branchinecta gaini in the area of the Wilhelm Archipelago Year Island Water body Coordinates Abbreviation Researcher 2007 Uruguay Is. Pond 1 65°14'18"S 64°13'30"W P1 Trokhymets V. 2007 Galindez Is. Pond 2 65°14'55"S 64°14'43"W P2 Trokhymets V., Dykyy I. 2008 Galindez Is. Pond 2 65°14'55"S 64°14'43"W P2 Trokhymets V. 2008 Skua Is. Rock pool 1 65°15'18"S 64°16'28"W RP1 Trokhymets V. 2008 Mitina Is.* Pond 3 65°14'11"S 64°18'31"W P3 Trokhymets V. 2010 Berthelot Is. Pond 4 65°19'42"S 64°08'40"W P4 Dykyy I. 2010 Galindez Is. Pond 2 65°14'55"S 64°14'43"W P2 Dykyy I. 2010 Petermann Is. Pond 5 65°10'02"S 64°08'00"W P5 Dykyy I. 2010 Uruguay Is. Lake 1 65°14'05.4"S 64°13'20.5"W L1 Dykyy I. 2010 Winter Is. Rock pool 2 65°15'00"S 64°15'47"W RP2 Dykyy I. 2010 Mitina Is.* Pond 3 65°14'11"S 64°18'31"W P3 Dykyy I. 2020 Irizar Is. Pond 6 65°13'08.7"S 64°12'01.2"W P6 Trokhymets V. 2020 Irizar Is. Rock pool 3 65°13'08.5"S 64°12'00.4"W RP3 Trokhymets V. 2020 Irizar Is. Rock pool 4 65°13'08.5"S 64°12'01.6"W RP4 Trokhymets V. 2020 Irizar Is. Rock pool 5 65°13'08.4"S 64°12'01.2"W RP5 Trokhymets V. 2020 Irizar Is. Pond 7 65°13'08.5"S 64°12'02.6"W P7 Trokhymets V. 2020 Irizar Is. Pond 8 65°13'10.2"S 64°11'58.2"W P8 Trokhymets V. 2020 Irizar Is. Rock pool 6 65°13'10.5"S 64°11'55.3"W RP6 Trokhymets V. 2020 Eight Is.* Rock pool 7 65°13'32.7"S 64°12'35.7"W RP7 Trokhymets V. 2020 Eight Is.* Rock pool 8 65°13'32.6"S 64°12'35.8"W RP8 Trokhymets V. 2020 Eight Is.* Rock pool 9 65°13'33.8"S 64°12'34.6"W RP9 Trokhymets V. 2020 Eight Is. * Rock pool 10 65°13'33.5"S 64°12'35.9"W RP10 Trokhymets V. 2020 Uruguay Is. Pond 9 65°14'16.4"S 64°13'18.7"W P9 Trokhymets V. 2020 Uruguay Is. Lake 1 65°14'05.4"S 64°13'20.5"W L1 Trokhymets V. 2020 Grotto Is. Rock pool 11 65°14'19.0"S 64°15'25.0"W RP11 Trokhymets V. 2020 Grotto Is. Rock pool 12 65°14'18.7"S 64°15'24.0"W RP12 Trokhymets V. 2020 Grotto Is. Rock pool 13 65°14'19.0"S 64°15'24.3"W RP13 Trokhymets V. 2020 Maly Berthelot Is.* Pond 10 65°20'07.7"S 64°10'29.2"W P10 Trokhymets V. 2020 Maly Berthelot Is.* Rock pool 14 65°20'13.1"S 64°10'25.8"W RP14 Trokhymets V. 2020 Maly Berthelot Is.* Rock pool 15 65°20'13.1"S 64°10'25.0"W RP15 Trokhymets V. 2020 Maly Berthelot Is.* Rock pool 16 65°20'13.0"S 64°10'28.1"W RP16 Trokhymets V. 2020 Maly Berthelot Is.* Rock pool 17 65°20'12.5"S 64°10'24.7"W RP17 Trokhymets V. 2020 Petermann Is. Rock pool 18 65°10'42.3"S 64°08'42.7"W RP18 Trokhymets V. 2020 Petermann Is. Pond 11 65°09'58.6"S 64°08'50.2"W P11 Trokhymets V. 2020 Black Is. Pond 12 65°15'28.4"S 64°17'04.6"W P12 Trokhymets V. 2020 Mitina Is.* Pond 3 65°14'11"S 64°18'31"W P3 Trokhymets V. 2020 Galindez Is. Pond 2 65°14'55"S 64°14'43"W P2 Trokhymets V. 2020 Galindez Is. Rock pool 19 65°14'54.8"S 64°14'43.8"W RP19 Trokhymets V. Note. * – unofficial name (an officially unnamed) Table 2 Freshwater bodies without Branchinecta gaini in the area of the Wilhelm Archipelago Year Island Water body Coordinates 2007 Cape Rasmussen* RP 65°14'51"S 64°05'05"W 2007 Petermann Is. P, RP, RP 65°10'25"S 64°08'06"W, 65°10'37"S 64°08'26"W, 65°10'34"S 64°08'25"W 2007 Locator Is. RP 65°10'44.4"S 64°29'31.4"W 2007 Galindez Is. RP 65°15'04"S 64°14'34"W 2008 Cruls I Is.* RP 65°11'48"S 64°32'19"W 2008 Cruls II Is.* RP, P 65°11'25"S 64°32'15"W, 65°11'23"S 64°32'18"W 2008 Locator Is. P 65°10'44"S 64°29'31"W 2010 Locator Is. P, P 65°10'44"S 64°29'27"W, 65°10'44"S 64°29'31"W 2010 Nob Is. RP 65°12'20"S 64°18'54"W 2010 Berthelot Is. RP 65°19'40"S 64°08'40"W 2010 Petermann Is. RP, P 65°10'39"S 64°08'41"W, 65°10'30"S 64°08'11"W 2010 Cruls I Is.* P 65°11'55"S 64°32'11"W 2010 Pléneau Is. RP 65°06'07"S 64°02'50"W 2010 Winter Is. P 65°14'54"S 64°15'33"W 2010 Skua Is. RP 65°15'03"S 64°16'14"W 2010 Rasmussen Is. RP 65°15'30"S 64°04'48"W 2010 Cape Rasmussen* RP 65°14'50"S 64°05'05"W 2020 Locator Is. P, RP, RP, RP, RP, RP, RP, RP, RP, RP, RP, RP, RP, RP 65°10'44"S 64°29'31"W, 65°10'43.6"S 64°29'30.1"W, 65°10'43.5"S 64°29'29.7"W, 65°10'43.4"S 64°29'33.4"W, 65°10'43.6"S 64°29'31.0"W, 65°10'44.1"S 64°29'31.2"W, 65°10'43.8"S 64°29'31.7"W, 65°10'43.1"S 64°29'34.1"W, 65°10'44.0"S 64°29'27.0"W, 65°10'43.6"S 64°29'33.1"W, 65°10'43.0"S 64°29'36.5"W, 65°10'43.4"S 64°29'33.4"W, 65°10'42.9"S 64°29'36.5"W, 65°10'43.7"S 64°29'35.7"W 2020 Blakytnookyi Is.* P, RP, RP, RP, RP, RP, RP, RP, RP, RP 65°12'21.8"S 64°18'42.0"W, 65°12'21.7"S 64°18'42.8"W, 65°12'20.7"S 64°18'38.0"W, 65°12'21.8"S 64°18'42.7"W, 65°12'25.7"S 64°18'51.0"W, 65°12'20.8"S 64°18'37.9"W, 65°12'18.4"S 64°18'25.7"W, 65°12'19.1"S 64°18'20.2"W, 65°12'18.9"S 64°18'18.6"W, 65°12'20.6"S 64°18'31.8"W 2020 Irizar Is. RP, RP, RP, RP, RP 65°13'11.8"S 64°12'01.9"W, 65°13'12.1"S 64°12'01.3"W, 65°13'11.7"S 64°12'02.6"W, 65°13'12.8"S 64°12'00.9"W, 65°13'13.1"S 64°12'00.4"W 2020 Eight Is.* RP, RP, RP, RP, RP, RP 65°13'32.3"S 64°12'35.6"W, 65°13'32.2"S 64°12'35.5"W, 65°13'32.6"S 64°12'35.9"W, 65°13'33.5"S 64°12'34.6"W, 65°13'33.4"S 64°12'35.4"W, 65°13'33.9"S 64°12'34.5"W 2020 Uruguay Is. RP, RP, RP, P 65°13'57.6"S 64°13'17.6"W, 65°13'57.3"S 64°13'21.8"W, 65°14'08.0"S 64°13'27.3"W, 65°14'18.1"S 64°13'29.8"W 2020 Grotto Is. RP, RP, RP, RP, RP, RP 65°14'19.9"S 64°15'24.3"W, 65°14'20.4"S 64°15'23.6"W, 65°14'22.2"S 64°15'19.1"W, 65°14'23.7"S 64°15'10.8"W, 65°14'21.9"S 64°15'13.7"W, 65°14'22.8"S 64°15'14.7"W 2020 Rasmussen Is. P, P, RP, RP, RP, RP, RP, RP, RP, P, P, P, RP, RP, RP 65°15'24.8"S 64°04'44.7"W, 65°15'24.7"S 64°04'43.3"W, 65°15'24.7"S 64°04'43.6"W, 65°15'24.9"S 64°04'43.2"W, 65°15'24.9"S 64°04'43.5"W, 65°15'25.8"S 64°04'47.1"W, 65°15'25.7"S 64°04'47.2"W, 65°15'25.8"S 64°04'47.2"W, 65°15'25.8"S 64°04'47.4"W, 65°15'29.2"S 64°04'42.1"W, 65°15'28.6"S 64°04'43.2"W, 65°15'28.9"S 64°04'44.0"W, 65°15'28.8"S 64°04'46.2"W, 65°15'29.2"S 64°04'45.6"W, 65°15'29.9"S 64°04'44.8"W 2020 Maly Berthelot Is.* RP, RP, RP 65°20'14.3"S 64°10'07.8"W, 65°20'09.0"S 64°10'18.3"W, 65°20'09.9"S 64°10'19.7"W 2020 Nob Is. RP, RP 65°12'20.2"S 64°18'54.2"W, 65°12'18.4"S 64°18'54.1"W 2020 Leopard Is. RP 65°15'17.0"S 64°17'26.4"W 2020 Galindez Is. P, RP, P, RP 65°14'53.1"S 64°14'43.5"W, 65°14'54.2"S 64°14'42.7"W, 65°14'43.1"S 64°15'22.5"W, 65°14'57.0"S 64°14'47.0"W 2020 Cape Tuxen PR, RP, P 65°16'04.0"S 64°06'58.8"W, 65°16'04.6"S 64°06'57.6"W, 65°16'02.2"S 64°07'03.3"W 2020 Hovgaard Is. PR, RP 65°07'09.6"S 64°04'24.3"W, 65°07'01.8"S 64°04'20.6"W 2020 Pléneau Is. PR 65°06'07.1"S 64°03'22.1"W 2020 Cape Rasmussen* P 65°14'49.7"S 64°05'05.6"W 2020 Cape Moot * PR 65°12'13.3"S 64°04'30.0"W 2020 Moot Is.* P 65°12'25"S 64°04'31"W 2020 Winter Is. PR 65°14'53.2"S 64°15'51.3"W 2020 Skua Is. PR, RP 65°15'03.3"S 64°16'14.1"W, 65°14'59.0"S 64°16'11.7"W 2020 Great Yalour Is.* PR, RP 65°14'06.0"S 64°09'28.0"W, 65°14'07.0"S 64°09'22.7"W Notes. L – lake, P – pond, RP – rock pool; * – unofficial name (an officially unnamed) Sample collection Samples were collected using a 2-liter sampler. Samples ranging in size from 5 to 20 L were filtered through a 100 µm mesh conical plankton mesh (Janiec 1991 ; Burian and Trokhymets 2017 ). We additionally used direct collection of fairy shrimp with a hand net (Jo et al. 2022 ) if these crustaceans were visually visible in the reservoir but were not sampled due to low abundance. This method makes it possible to conduct a quantitative assessment of copepods, but only a qualitative assessment (presence or absence) for fairy shrimp, since the latter have a more complex behavior and are not evenly distributed (Pociecha and Dumont 2008 ). Animals were fixed in 99% ethanol for further molecular genetic studies (Pokorný et al. 2024 ), and some individuals in 4% formaldehyde for morphological analysis (Pociecha and Dumont 2008 ). We also recorded salinity using salinity meter and water temperature by means a mercury thermometer. Taxonomic identification The investigation of B. gaini in samples from 2007, 2008, and 2010 was carried out in the laboratory of the Educational and Scientific Center "Institute of Biology and Medicine" of Taras Shevchenko National University of Kyiv. The study of B. gaini in 2020 was performed directly in the laboratory of the Ukrainian Antarctic Akademik Vernadsky station. Morphology analysis was done by means a stereomicroscope MBS-12. Adults B. gaini was taxonomically identified using minor structural features of the structure of the second antenna, gonopodia and genital segments of males (Dabay De Deés 1910; Jurasz et al. 1983 ; Rogers et al. 2020a ). Larvae were identified from illustrations in the article about the life cycle of this crustacean (Jurasz et al. 1983 ). Different stages of B. gaini development can be seen in Fig. 2 . Map constructions and photos Maps were generated with QGIS 3.16 using SCAR Antarctic Digital Database v7.7 2023 by Gerrish et al. ( 2023 ) and UK Polar Data Centre VERSION 7.3 (Version 1.0) by Gerrish ( 2020 ). Coordinate Reference Systems WGS 84 Antarctic Polar Stereographic EPSG:3031 (Fig. 1 ) and WGS 84 UTM zone 20N EPSG:32620 (Fig. 1 , 3 – 15 ) were used for map generation. All photos were taken and provided for publication by the first and second authors. Statistical analysis According to the results of Shapiro-Wilk normality test, data have not normality distribution. Therefore, the nonparametric Mann-Whitney-Wilcoxon test (Bauer 1972 ) was used to determine the effect of depth, salinity, and temperature on the presence or absence of B. gaini in freshwater bodies. Pearson's chi-squared test (Pearson 1900 ) was used to analyze the influence of presence of cyanobacterial mat, presence of Boeckella poppei (Mrázek, 1901) (Copepoda, Calanoida), and time sampling (month, year) on the presence or absence of B. gaini in reservoirs. The study used only reservoirs within islands where B. gaini had been previously confirmed (in previous studies or during our study). Although freshwater bodies on other islands may be optimal for the species, there is currently no evidence that the species has been introduced there by vectors. Therefore, including these water bodies in the statistical analysis would bias the results. RStudio (v. 1.4.1106, R 4.0.5) is used for all statistical data processing. Results Branchinecta gaini was registries in two freshwater bodies of Uruguay and Galindez Islands out of the four examined islands and the Cape Rasmussen in 2007, three reservoirs of three islands from six examined islands in 2008, six freshwater bodies of six islands from 12 examined islands and the Cape Rasmussen in 2010, and 27 reservoirs of nine islands from 20 examined islands and three continental capes in 2020 (see Tables 1 , 2 ). Some samples were taken from the same freshwater body (for example, on Galindez Island) in different years of research, so the number of islands with finds of this crustacean is not a simple sum of the studied islands for different years. Branchinecta gaini was found in the 32 freshwater bodies of 12 islands in the Wilhelm Archipelago (Fig. 3 ). This anostracan was registries for the first time in reservoirs of 11 islands. Next, we will consider in more detail the reservoirs and islands where representatives of B. gaini were registered. 1. Uruguay Island is one from the Argentine Islands group of Wilhelm Archipelago (Fig. 4 a). It is located in the Bellingshausen Sea at a distance of 2 km to the northeast of Galindez Island and about 6 km from the coast of Kyiv Peninsula. The island consists of the northern and southern parts, connected by a narrow isthmus. P1 is located on the southern part of the island, on the left side of the central rocky ridge, if going from the south to the north (Fig. 4 b). It is located at an altitude of 15 m above sea level, has dimensions in the maximum section of about 50x20 m and a depth of up to 1.5 m. The bottom is rocky, and the walls are covered in places with a brown layer of cyanobacterial mat. Water comes from melting snow and ice. There is no vegetation near the pond. One adult specimen of B. gaini was detected in P1 in March 2007. Another sample was taken from this pond in April 2020. There were no crustaceans, but this can be explained by the fact that the reservoir was already covered with a five-centimeter layer of ice. A hole had to be drilled in the ice in order to take a sample. We can assume that the adults of B. gaini could have laid wintering eggs and died. P9 is located on the southern part of the island, on the right side of the central rocky ridge (Fig. 4 c). It is located at an altitude of 11 m above the sea level, has dimensions in the maximum section of about 120x50 m (the size of the this freshwater pond was accurately determined later and turned out to be larger than it was measured at the time of sampling, when the reservoir was partially frozen and covered with snow) and a depth of up to 0.7 m. The bottom is rocky, and the walls are covered in places with a brown layer of cyanobacterial mat. Water comes from melting snow and ice. There is no vegetation near the pond. Several adult individuals of B. gaini were registries under a thin layer of ice in P9 in April 2020. Elongated L1 is located in the center of the island’s northern part in a depression between rocky ridges (Fig. 4 d–e). It is located at an elevation of 40 m and has dimensions of about 300x80 m (it were determined later similarly to P10) and a maximum depth of 8 m in the northern part of the lake. It is the largest lake in the area of Argentine Islands. The bottom is stone, in places covered with organic matter of green color; the walls are covered with a thin cyanobacterial mat. Water comes from melting glaciers and snow. Nearby are small fields of moss and lichens. L1 is one of the few reservoirs in the region of our studies that does not freeze to bottom in winter and where representatives of the fauna can actively function in the coldest season. The lake is connected by canals to a subglacial lake. The latter is located under a glacial dome about 12 m thick and has a depth of 9 m. The connection of these two lakes confirms the fact that a hole was made in the ice dome by thermal drilling and parts of the limbs of B. gaini were found in the sample taken (Chernov et al. 2020 ). The existence of this crustacean in a closed subglacial ecosystem is hardly possible, since this species is not a troglobiont. Thus, L1 is a unique ecosystem in which classic groups of Antarctic freshwater hydrobionts and representatives of troglobionts can potentially be found. It was previously proposed to use L1 as the Base station №2 for continuous monitoring of B. poppei (Trokhymets 2024). However, this freshwater reservoir is also optimal for long-term monitoring of B gaini and other aquatic biota, as research can be conducted even in winter under favorable weather conditions (when the island is accessible by open water or ice). Therefore, we propose to consider this reservoir as the “Basic freshwater hydrobiological station №1” for permanent monitoring of hydrobionts and the Base station №2 for long-term monitoring of B. gaini and B. poppei in this region of the Wilhelm Archipelago (Table 3 ). Branchinecta gaini was registered in L1 in February 2010 and March 2020. Nine females, four males and six juveniles (19 in total) were collected in 2010. Three females and 10 juveniles (13 in total) were caught in 2020. Samples were taken for the purpose of monitoring hydrobionts every week from March 10 to April 14, 2020. Branchinecta gaini was present in the samples every times, although their number decreased. So, three live (one female and two males) and one dead individuals were found in the sample on April 14. Table 3 Proposed base stations for hydrobiological research in this region of the Wilhelm Archipelago Base station Island FB Coordinates Object of monitoring BFHS №1 Uruguay Is. Lake 1 65°14'05.4"S 64°13'20.5"W All hydrobionts BFHS №2 Skua Is. Lake 65°15'10"S 64°15'40"W All hydrobionts Basic station № 1 Irizar Is. Pond 6 65°13'08.7"S 64°12'01.2"W Branchinecta gaini , Boeckella poppei Basic station № 2 Uruguay Is. Lake 1 65°14'05.4"S 64°13'20.5"W B. gaini , B. poppei Basic station № 3 Galindez Is. Pond 2 65°14'55"S 64°14'43"W B. gaini FB 65°14'56.7"S 64°14'47.0"W B. poppei Notes. FB – freshwater body; BFHS – “Basic freshwater hydrobiological station”; Pond 7 from Irizar Island, as well as the freshwater bodies of Eight and Grotto Islands can be an alternative for long-term monitoring B. gaini and B. poppei 2. Galindez Island is one from the Argentine Islands group (Fig. 5 a). It is located in the Bellingshausen Sea at a distance 7 km from the continental coast of Kyiv Peninsula. P2 is located near the highest point of the island (Fig. 5 b-c). This reservoir is very similar to the rock pool, but we will consider it as a pond according to the classification used. The pond has a more or less rounded shape and dimensions of approximately 4x4 m. Depth up to 30 cm. The reservoir is formed as a result of melting snow. Nearby, there are only bare rocks with small patches of moss and lichen. A brown cyanobacterial mat 1 mm thick is visible on the walls. Branchinecta gaini was found in P2 in March 2007 (12 adult specimens), in February 2008 (10), in January 2010 (9), and in February 2020 (15). Thus, this is the only freshwater body in which these crustaceans were registered during all four years of research. We are offered this reservoir as the Base station №3 for the long-term monitoring of B. gaini population dynamics. In addition, it is proposed to move the Base station № 3 for monitoring of B. poppei from the Grotto Island (Trokhymets et al. 2024 ) to Galindez Island (Table 3 ), where a new population of this copepod was recently discovered (Nabokin et al. 2023 ). RP19 are located on the top of a flat hill. The reservoir is dimensions of 3x3 m and a depth of up to 0.3 m. The bottom is rocky and covered with organic matter. The walls are covered with a brown a layer of cyanobacterial mat. Water comes from melting snow. Water was opaque at the time of sampling, which is due to the bloom of phytoplankton. Nearby there are patches of moss and lichens. Branchinecta gaini was found in March 2020. 23 sexually mature representatives were registries in the sample. 3. Skua Island is one from the Argentine Islands (Fig. 6 a). It is located in the Bellingshausen Sea at a distance of 0.7 km to the southwestern from the Ukrainian Antarctic Akademik Vernadsky station on neighboring Galindez Island and about 6 km from the coast of Kyiv Peninsula. RP1 is located on the terrace of the slope on the southwest coast of Skua Island. The shape of this freshwater body is elongated polygonal. Its dimensions reach 2x1 m and the depth is 0.3 m. The reservoir was formed as a result of melting snow. Nearby are small patches of moss and lichen. The stone bottom is covered in places with a layer of green-brown organic matter (Fig. 6 b). A brown cyanobacterial mat (1 mm thick) overgrown on the walls. Seven sexually mature specimens of B. gaini were selected within this reservoir in February 2008. In addition, one of the largest freshwater bodies in this region of the Wilhelm Archipelago deserves special attention (Fig. 6с). This reservoir is located in the northern part of the island, not far from the ice dome and a number of stone hills (65°15'10"S 64°15'40"W). It was formed as a result of the melting of the glacier of the island and snow. Much of it is covered with ice, so it is difficult to determine the exact dimensions. This reservoir suffered a maximum thawing in February-March 2020, resulting in was possible to determine its approximate dimensions: the maximum size was 200x85 m. The reservoir has maximum depths more than 2 m. In this regard, we consider this freshwater body as a lake. Crustaceans were not detected by visual monitoring, but a more detailed analysis of hydrobionts is required. Unfortunately, it was not possible to fundamentally investigate of hydrobionts in this freshwater body in 2020. In the future, it will be possible to trace the processes of settlement of new biota within the reservoir. In addition, it is convenient for research, as it is located near Galindez Island. We propose to consider this reservoir as the “Basic freshwater hydrobiological station №2” for constant monitoring of hydrobionts (Table 3 ). 4. Mitina Island (unofficial name, an officially unnamed) is one from the small islands group The Barchans from the Argentine Islands group (Fig. 7 a). The island located most northeast of other The Barchans and in the Bellingshausen Sea at a distance of 2 km to the west from the Galindez Island and about 8.5 km from the continental coast of Kyiv Peninsula. P3 is located on a stone plateau of the northwestern coast of the island at an altitude of 12 m (Fig. 7 b). The shape of this freshwater body has the appearance of an irregular quadrangular with unequal sides. The size is 4x3 m, and its depth is up to 0.3 m. P3 was formed as a result of melting snow. There are small patches of moss and lichen nearby. The bottom is stony, in the deepest part of semi-decomposed moss have accumulated. A thin layer of brown cyanobacterial mat covers the walls and bottom of the reservoir. Branchinecta gaini were collected in this reservoir in February 2008 (14 sexually mature specimens), in February 2010 (7), and in February 2020 (24). 5. Berthelot Island is one from the Berthelot Islands group (Fig. 8 a). It is located in the Bellingshausen Sea at a distance of 10 km to the southeast of Galindez Island and about 3.5 km from the continental coast of Kyiv Peninsula. P4 is located in the northern part of the island, at the base of the thin peninsula, which is directed to the northeast. The reservoir was formed on a stone terrace near the hill. Stone blocks are scattered along its coast, which form a depression of a polygonal shape (Fig. 8 b-c). Its total area reaches approximately 12 m 2 , and the depth is 0.4 m. P4 is flowing, and its level is maintained thanks to melted snow. All around are large fields of moss and patches of lichen. At the bottom is an accumulated layer of semi-decomposed moss, and the walls are covered with a layer of cyanobacterial mat. Three sexually mature specimens of B. gaini were registries in the reservoir in January 2010. 6. Petermann Island is located in the Bellingshausen Sea at a distance of 9 km northeast of Galindez Island and about 2 km from the continental coast of Kyiv Peninsula (Fig. 9 a). P5 is located on the northeastern part of the island at an altitude of 7 m above sea level (Fig. 9 b). The reservoir is formed in a stone gorge and has an L-shape. Its dimensions reach 7x2 m, and the depth is 0.4 m. The rocky walls are covered with a thick layer of brownish-red cyanobacterial mat (Fig. 9 c), and there is a small amount of silt from decomposed moss at the bottom. Water comes from melting snow. There are small patches of carpet moss up to tens of centimeters in size and lichens nearby. 20 sexually mature specimens of B. gaini were collected in March 2010. RP18 is located in the coastal area of ​​the southern part of the island at a height of 8 m above sea level (Fig. 9 d). The reservoir has an irregular shape that vaguely resembles a cross. Its maximum dimensions reach 3x2 m, and the depth is 0.3 m. It is located in a hollow, on a slope between large stone blocks. The walls have a thin layer of brown cyanobacterial mat; the bottom is covered with a several-centimeter layer of silt and half-decomposed moss. Meter-long patches of moss, among which there are small (up to 20 cm) patches of Prasiola algae, are located on the bank of the freshwater body. 15 adults of B. gaini were collected in February 2020. In general, this reservoir is the only one in our studies with the presence of anostracans, which was significantly influenced by the local avifauna. The fact is that a few tens of meters above and below this reservoir there are small colonies of the Gentoo Penguin ( Pygoscelis papua (Forster, 1781)). Accordingly, a small amount of feathers and guano of birds entered the reservoir together with the melt water. As a result, the water is opaque due to the presence of organic matter, and feathers float on the surface. RP18 is not as polluted as the reservoirs in the middle of the penguin colony and where crustaceans have never been found. P11 is located in the northern part of the island at an altitude of 16 m above sea level (Fig. 9 e). The rhomboid reservoir is formed in a stone hollow. It has dimensions of 5x3 m and a depth of up to 0.4 m. The walls are covered with a thin layer of brown cyanobacterial mat to a depth of up 30 cm. There is some silt at the bottom from decomposed moss. Water comes from melting snow and ice. Patches of moss ranging in size from centimeters to meters and lichens are nearby. A large number of anostracans were found feeding by cyanobacterial mat on stones during the visual observation in February 2020. 62 individuals of B. gaini were registered in the sample (56 adults, one juvenile, and five larvae). 7. Winter Island is one from the Argentine Islands group (Fig. 10 a). It is located in the Bellingshausen Sea at a distance of 0.15 km from the Ukrainian Antarctic Akademik Vernadsky station on neigh boring Galindez Island and about 6.5 km from the continental coast of Kyiv Peninsula. RP2 has an oval shape and is located near the coast (Fig. 10 b), opposite Skua Island. It is formed in a hollow between stone blocks. The size of the reservoir is 3x2 m, and the depth reaches 0.4 m. The walls are covered with a thin layer of brown cyanobacterial mat, and on the gravel bottom is a layer of decomposed and semi-decomposed moss up to 5 cm thick. Water comes from melting snow and ice. Around this freshwater body are fields of moss and lichens. Three adults of B. gaini were selected in February 2010. 8. Irizar Island is one from the Argentine Islands group (Fig. 11 a). It is located in the Bellingshausen Sea at a distance of 3.5 km to the northeast of Galindez Island and about 6 km from the continental coast of Kyiv Peninsula. The elongated polygonal P6 is located on the terrace of the slope of the northernmost rocky ridge of the island at an altitude of 15 m above sea level (Fig. 11 b). Its dimensions reach 6x2 m, and the depth is 0.5 m. The stone walls are covered with a thin layer of brown cyanobacterial mat, and at the bottom is a layer of decomposed and semi-decomposed moss silt (up to 0.1 m). Water enters the reservoir from melting snow. There are small moss fields and lichens around. Seven sexually mature individuals of B. gaini were found in February 2020. P6 was chosen as the Base station №1 for long-term monitoring of the phenology of B. gaini and B. poppei (Trokhymets et al. 2024 ) (Table 3 ). RP3 is located close to the shore, slightly to the east of P6. The reservoir is located in the depression of the terrace at a height of 12 m above sea level and has a triangular shape. Its dimensions reach 1.5 x 0.5 m, and the depth is up to 0.3 m. The stone walls and bottom are covered with a thin layer of cyanobacterial mat. Water in the reservoir comes from melting snow. Two B. gaini adults were found in the samples from RP3 in February 2020. RP4 and RP5 are located to the north of P6 (Fig. 11 c). The spindle-shaped PR4 is formed on a rock terrace at a height of 14 meters above sea level. It has dimensions of 2x1 m and a depth of up to 0.3 m. The quadrangular PR5 is located on the rock terrace at a height of 15 m, a few meters and slightly higher than RP4. It has dimensions of 2x1.5 m and a depth of up to 0.4 m. The walls of both reservoirs are covered with a thin layer of brown cyanobacterial mat, and the bottom is covered with a thin layer of organic matter from decomposed moss. They receive water as a result of melting snow. A small amount of moss (tens of centimeters) and lichens are placed near them. Accordingly, five and six sexually mature individuals of B. gaini were found in both freshwater bodies in February 2020. P7 formed on the terrace of the rock slope at a height of 12 m above sea level, somewhat to the north-west of the other reservoirs. It has the shape of an irregular quadrangle, the dimensions are 10x3 m and the depth is 1 m. The stone walls are covered with a thin layer of brown cyanobacterial mat; the bottom is free of silt. One sexually mature individual of B. gaini was caught in March 2020. P8 is located on a terrace on one of the hills of the island at an altitude of 21 m above sea level (Fig. 11 d). The round reservoir has dimensions of 20x20 m and a depth of up to 1 m. The walls are covered with a thin layer of brown cyanobacterial mat up to 30 cm deep, and the bottom of small stones contains a thin layer of silt from decomposed moss. Water will fill the reservoir as a result of melting snow. Moss and lichens grow around. Seven B. gaini juveniles and larvae were detected in the sample in February 2020. It is worth noting that this is the only freshwater body of the island, where larval stages and juveniles of these crustaceans were found. There were no sexually mature individuals. RP6 is located in a depression on a rock slope at an altitude of 8 m above sea level. Its dimensions are 2x1.5 m, and the depth is 0.3 m. There is a thin layer of brown cyanobacterial mat on the walls. The bottom is stony, in places covered with a layer of decomposed moss. Water enters the reservoir as a result of melting snow. There are small patches of moss and lichen around. It is worth noting that at the time of sampling, the reservoir was already covered with a three-centimeter layer of ice. Three B. gaini adults were detected in the sample in March 2020. 9. Eight Island (unofficial name, an officially unnamed) is one from the Argentine Islands group (Fig. 12 a). It is located in the Bellingshausen Sea at a distance of 3 km to the northeast of Galindez Island and about 6 km from the continental coast of Kyiv Peninsula. The island consists of northern and southern parts connected by an isthmus. Samples were taken within the southern part of the island. RP7 is located on the terrace of the northern slope of this part of the island at an altitude of 8 m above sea level (Fig. 12 b). It has the shape of a triangle, the base of which is placed under the ice, and the sharp corner is directed down the slope. Its dimensions are 3x2 m, and the depth is up to 0.3 m. The stone walls are covered with a thin layer of cyanobacterial mat, and at the bottom there is silt from semi-decomposed moss. Water constantly flows into this reservoir due to the melting of ice and snow. Excess water flows below and forms a cascade of small rock pools, where crustaceans have also been found. However, this is a single system and therefore these rock pools were not considered as separate bodies of water. Nearby there are small areas with mosses and lichens. Five sexually mature individuals of B. gaini were found in the sample in February 2020. Several separate rock pools were also found in this area, three of which were found to contain crustaceans. RP 8–10 have a rounded or polygonal shape, dimensions 2–1x1–0.5 m and a depth of 0.2–0.3 m (Fig. 12 c). The walls and bottom of these reservoirs are covered with a cyanobacterial mat. Water comes from melting snow and ice. Several sexually mature individuals of B. gaini were registered in samples in February 2020 (RP8–3 specimens, RP9–2, RP10–2). 10. Grotto Island is one from the Argentine Islands group (Fig. 13 a). It is located in the Bellingshausen Sea at a distance of 0.4 km to the north of Galindez Island and about 7 km from the continental coast of Kyiv Peninsula. The elongated RP11 is located on the northwest coast of the island 20 m from the shore and at an altitude of 5 m above sea level. Its maximum dimensions reach 10x1 m, and the depth is 0.4 m. The reservoir is located in a gap between large stone blocks (Fig. 13 b). The stone walls and bottom are covered with a layer of brown cyanobacterial mat 2 mm thick, and at the bottom in places there is silt of decomposed moss. 70 sexually mature individuals of B. gaini were found in the sample from the deepest part of RP11 in March 2020. Nearby are two more small freshwater bodies RP12 (Fig. 13 c) and RP13. The dimensions of RP12 are 4x2 m, RP13 are 2x1 m. The shape of these reservoirs has the appearance of irregular polygons. Their depth reaches 0.2–0.3 m. The walls of the reservoirs are covered with a thin layer of cyanobacterial mat, although in some places its thickness reached 2 mm. Water comes as a result of melting snow. Accordingly, 11 and five sexually mature individuals of B. gaini were caught in reservoirs in March 2020. There are other shallow rock pools in the area with lots of semi-degraded and decomposed moss where no anostracans were found. 11. Maly Berthelot Island (unofficial name, an officially unnamed) is one from the Berthelot Islands group (Fig. 8 a). It is located in the Bellingshausen Sea at a distance of 11 km to the southeast of Galindez Island and about 5 km from the continental coast of Kyiv Peninsula. The elongated P10 is located on the elevation of the northern part of the island at an altitude of 39 m above sea level (Fig. 8 d). Its dimensions are 20x5 m, and the depth is 0.5 m. The bottom is stony, in places covered with a layer of decomposed and semi-decomposed moss. On the walls in places there is a brown cyanobacterial mat up to 2 mm thick. Mossy fields and lichens are located around the reservoir. The water is transparent; it replenishes the reservoir as a result of melting snow. 83 adults of B. gaini were selected in March 2020. RP14 is located on the highlands of the central part of the island at an altitude of 41 m above sea level. The shape of the reservoir somewhat resembles the letter W. Its dimensions are 5x2 m, depth 0.2 m. The bottom is stony, covered with a layer of decomposed and semi-decomposed moss. Along the edges of the freshwater body, moss occupies the entire space from the bottom to the surface of the water, and only in its central part is there free water, where anostracans are concentrated. The walls are covered with a thick brown layer of cyanobacterial mat. Smaller rock pools of various shapes (RP15–17) are located around. Their size does not exceed several m 2 , and the depth is up to 0.2 m. On their stone bottom there is semi-decomposed moss, and the walls are covered with a layer of cyanobacterial mat. Sexually mature individuals of B. gaini were found in all four rock pools in March 2020: RP14–5 specimens, RP15–3, RP16–7, and RP17–11. 12. Black Island is one from the Argentine Islands group (Fig. 14 a). It is located in the Bellingshausen Sea at a distance of 1.5 km southwest of Galindez Island and about 7 km from the mainland coast of the Kyiv Peninsula. P12 is located on the western part of the lake, 15 m from the shore at a height of 5 m above sea level. The reservoir has dimensions of 10x4 m and a depth of up to 0.4 m. Stone walls and the bottom up to a depth of 30 cm are covered with a layer of brown cyanobacterial mat up to 2–3 mm thick. At the bottom there is a large amount of silt from decomposed moss (Fig. 14 b), and near the shore is semi-decomposed and fresh moss. Water comes from melting snow. Meter-sized moss fields are located close to the reservoir. There are lichens. 37 B. gaini individuals were found in the sample (28 sexually mature individuals and 9 juveniles) in February 2020. An assessment of the influence of certain factors on the presence of B. gaini in water bodies gave the following results. Mann–Whitney–Wilcoxon test results indicate the depth of sampling affected the possibility of encountering B. gaini – on average, samples were found more often at greater depths (Table 4 ). Despite this, this species was recorded at all depths within the study – from 0.1 m to 1 m. However, B. gaini were found in water bodies 0.1 m deep only once. Water temperature and salinity did not affect the probability of encountering individuals of this species. In general, these two indicators varied within relatively narrow ranges. Table 4 Comparison of mean of the water body depth, water temperature, and salinity, and their impact on Branchinecta gaini presence in the water body Presence of B. gaini Mean ± SE Median (Q25% – Q75%) Number of samples W** p -value Degrees of freedom Depth, m Yes 0.42 ± 0.04 0.30 (0.30–0.40) 38 928.5 0.0004 69 No 0.35 ± 0.07 0.20 (0.20–0.30) 33 t, °C Yes 2.04 ± 0.11 2.20 (1.55–2.60) 32 418.5 0.5127 60 No 2.19 ± 0.10 2.20 (2.10–2.60) 29 Salinity, ‰ Yes 0.0817 ± 0.0191 0.0570 (0.0425–0.0640) 27 487.5 0.0661 52 No 0.0787 ± 0.0198 0.0490 (0.0400–0.0550) 28 Note. W** – Mann–Whitney–Wilcoxon test statistic value Chi-squared analysis demonstrates the absence of dependence of the presence of B. gaini in the catch on the presence of B. poppei in the reservoir (_X_1 = 2.797, _p_ = 0.0944), month (_X_3 = 0.853, _p_ = 0.3557) or year (_X_3 = 3.416, _p_ = 0.0646) of material collection. The presence of cyanobacterial mats statistically affected the presence of this species in a water body (_X_1 = 4.255, _p_ = 0.0391). However, few reservoirs were without mats for the test results to be considered truly significant too. Only six times were samples taken in reservoirs where mats were not recorded, but B. gaini was not found in any of them. Discussion The distribution of B. gaini in the area of ​​the Wilhelm Archipelago was studied in freshwater reservoirs of the islands and capes of the Antarctic coast. The territory of our research stretched from north to south for 25 km from Hovgaard Island to the Berthelot Islands group and 22 km from west to east from the Cruls Islands group to the continental coast. This made it possible to obtain new data on the freshwater fauna of this Antarctic region. Long-term studies have shown that the number of reservoirs and islands, within which representatives of B. gaini were found, increased over time: years – 2007 → 2008 → 2010 → 2020, the number of reservoirs – 2 → 3 → 6 → 27, the number of islands – 2 → 3 → 6 → 9. Some islands and reservoirs are repeated in studies for different years, but the general trend remains the same. This dependence is related to the total number of investigated water bodies and islands/capes. The fact is that this number of them also mostly increased over time: the number of studied reservoirs – 8 → 7 → 18 → 111, the number of studied islands/capes – 5 → 6 → 13 → 23. An important aspect of obtaining new data on the distribution of B. gaini also became the hydrobiologists from the Ukrainian Antarctic Akademik Vernadsky station on Galindez Island, since it the work of the first author was the beginning of the modern study of this crustacean in this region in 2007–2008. The active study of the freshwater fauna of the region actually began from that moment, growing over time. In addition, this species was first described from the freshwater reservoirs of Petermann Island and small adjacent islands of the Wilhelm Archipelago back in 1910 (Dabay De Deés 1910). Therefore, it is unlikely that such an active resettlement could have occurred during the 14-year period of research (from 2007 to 2020), given that almost 100 years passed from the first finding of this species within the Wilhelm Archipelago to the beginning of our research. The species, which was in this region even 100 years ago, had enough time to populate a significant part of the freshwater bodies of this region (Polishuk et al. 2009 ; Chernov et al. 2020 ). On the other hand, this species was not registered by us within the 15 studied islands and capes. These areas contain reservoirs with the necessary living conditions for these crustaceans. Moreover, a number of water bodies without B. gaini were found on the islands where this species was recorded. It can be concluded that this anostracan is a common species for this region, which is gradually spreading to new territories. This confirms the fact that B. gaini has not disappeared from any reservoirs where it was previously registered during our research (P2, P3, and others), nor has it appeared where it was previously absent (for example, the freshwater reservoirs of Locator Island). First, we will consider the history of the appearance of B. gaini in the Antarctic in order to better understand the modern mechanisms of the distribution of the southernmost species of anostracans (Rogers et al. 2020b ). For this, it is necessary to consider the main theories of the appearance of this crustacean in the Antarctic, which are distribution from other regions of the planet and endemism. Most scientists deny the possibility of endemism of this crustacean, since it is unlikely that its eggs could survive the freezing of water bodies for hundreds of years. In addition, the active phase of the life cycle of B. gaini takes place during the Antarctic summer, when optimal conditions for its development occur, namely liquid water and positive temperatures (Jurasz et al. 1983 ). Such a life cycle is facilitated by the metabolic eurythermy characteristic of this species (Peck 2004 , Pociecha 2007 ). It is not characteristic of the majority of Antarctic terrestrial invertebrates, which are dominated by slow life cycles with activation during the Antarctic summer. Thus, B. gaini is not a classic Antarctic species. It did not adapt to Antarctic conditions, but used the classic set of adaptations of anostracans to survive adverse conditions of existence. The latter include resistance to adverse egg conditions and their ability to spread passively, as well as the metabolic flexibility of larvae, juveniles, and sexually matured representatives (Hawes 2009 ). Although the feeding behavior of the detritophagous B. gaini is somewhat different from other filter feeders of the genus Branchinecta (Hawes 2008 ), its life strategy has little to do with adaptation to Antarctic conditions (Peck et al. 2006 ). This refutes the theory of endemism and favors the theory of spread of this anostracan from South America to the freshwater ecosystems of Antarctica. Branchinecta gaini eggs were most likely transferred from the freshwater bodies of Chile to the reservoirs of different groups of islands (Falkland Islands, South Georgia, South Orkney Islands, South Shetland Islands), and directly to Antarctica (James Ross Island) using passive dispersal vectors. In general, settlement in the Antarctic took place both from South America and from the corresponding groups of islands. But these were not unidirectional movements of populations, since the most likely transfer of this species could also occur in the opposite direction (Hawes 2009 ). Further, gradual resettlement took place from James Ross Island in the direction of Marguerite Bay, where environmental conditions allowed representatives of this species to survive (Hawes 2008 ) The formation of multiple populations began with local resettlement events when B. gaini reached new regions of the Antarctic (Hawes 2009 ). The main theory of colonization of B. gaini of freshwater bodies of Antarctic is the spread of this species at the stage of eggs in the last 10000 years. Accordingly, supporters of this approach believe that this species appeared in the reservoirs of the Antarctic islands after The Penultimate Glacial Maximum. It lasted 20-18000 BP and at that time Antarctica was almost completely covered with ice (Ralph 1967 ). Previously, the oldest findings were considered to be eggs' microfossils of B. gaini with the James Rose Island aged about 4200 BP (Björck et al. 1996 ) and from the Signy Island of South Orkney Islands aged about 5500 BP (Jones et al. 2000 ). Later the eggs' microfossils of this crustacean on the Horseshoe Island in Marguerite Bay aged about 9300 BP was found (Hodgson et al. 2013 ). However, the molecular clock analysis of COI and the analysis of the geographical distribution haplotypes of B. gaini were recently conducted. The results of these studies indicate that this species has survived the last glacial period in an unknown refuge in Antarctic at the moment (Pokorný et al. 2024 ). Secondly, the species must survive and gain a foothold when entering new territories. As we have already understood, this is mainly facilitated not by adaptation to extreme conditions of existence in B. gaini , but characteristic of this group of animals by general organizational features. Let's consider the main ones against the background of environmental factors that can limit the spread of this species: 1) Branchinecta gaini withstands a wide range of fluctuations of a number of abiotic factors, the key of which for survival in the extreme conditions of the Antarctic is temperature. Representatives of this species have wide amplitude of physiological flexibility, which allows them to withstand temperature fluctuations of up to 50°C. Mature individuals can withstand temperatures up to 25°C during the Antarctic summer, and overwintering eggs tolerate temperatures down to -25°C (Peck 2005 ). Adults do not have anti-incision proteins in the hemolymph, the crystallization temperature of which is -5°C (Hawes et al. 2008 ). It is worth noting that as a result of global warming and other changes, the habitat of B. gaini is also gradually being transformed. The active stages of the development of this species receive more time that improved conditions for the passage of the main processes inherent in living organisms (growth, nutrition, and reproduction). The temperature also affects the amount of oxygen, which is necessary for the life processes of B. gaini . Representatives of this species began to use more oxygen with the increase in water temperature and vice versa (Pociecha 2007 ). This, in turn, makes it possible to extend the time of active stages of development, since adults can exist even under ice. At the same time, the lack of oxygen due to the ice cover of the water surface is compensated for a certain time by the decrease in oxygen needs of mature individuals of anostracans. We observed how for three weeks (March-April 2020) some reservoirs of the Uruguay and Irizar islands were covered with a layer of ice, but live crustaceans were still present there at the time of sampling. This important aspect allows you to extend the maturation time of eggs in females that hatched later. Accordingly, this can increase the number of overwintering eggs within a certain reservoir. This, in turn, increases the number of mature individuals for the next year, and also increases the probability of these eggs being transferred to other reservoirs. Another important abiotic factor that can influence the vital activity of B. gaini is water salinity. On the one hand, salinity stimulates immature and mature Antarctic Fairy Shrimp, but at low concentrations. On the other hand, the ingress of seawater into freshwater reservoirs during storms and an increase in the concentration of salts to 20 psu led to the death of all representatives of this species except for the egg stage (Pociecha and Dumont 2008 ). Other scientists confirm that even a slight increase in salinity is a limiting factor for B. gaini (Hawes et al. 2008 ). This is due to the fact that the cuticle of these crustaceans is permeable for fluids and in salt water the animal begins to lose fluids, which leads to its death. Accordingly, the osmoregulation of B. gaini shows that it is a classic freshwater species without adaptations to existence at elevated concentrations of salts in water (Ralph 1967 ); 2) An important reason for the success of B. gaini in the Antarctic is the almost complete absence of antagonistic interactions in the influence of the biotic factor within the habitat. Anostracans are the largest invertebrates in Antarctic freshwaters that are defenseless against predators. Therefore, their survival strategy is to occupy reservoirs where predators are absent. The main predator that preys on anostracans in different regions of the planet is fish (Ralph 1967 ), and they live only in marine ecosystems in Antarctica (Trokhymets et al. 2022 ). Antarctic freshwater bodies are characterized by an almost complete absence of invertebrate and chordate predators (Laybourn-Parry 2002 ). According to our observations, the only groups of animals that can eat B. gaini are birds. Other researchers also reported about eat of anostracans by waterfowl (Green et al. 2005 ). We have repeatedly observed how, the South Polar Skua ( Stercorarius maccormicki Saunders, 1893) bathed in freshwater ponds and rock pools in the area of ​​the Argentine Islands group. A few times it hunted B. gaini , but it was more like an instinct when a predator grabs a moving object. This specie of anostracans does not make up a significant part of the bird's diet, and such hunting for small prey is energetically unprofitable. Branchinecta gaini is almost devoid of interspecies competition for food and living space in the freshwater bodies of the Antarctic. It competes only for a small part of the food diet (small bacteria and large diatoms) with the copepod B. poppei (Pociecha and Dumont 2008 ). Our research showed that although in a number of cohabitation reservoirs (for example, on Grotto Island) the numbers of copepods were low, but Chi-squared analysis demonstrates the absence of dependence of the presence of B. gaini in the catch on the presence of B. poppei in the reservoir. Regarding the influence of parasites, it is worth mentioning the hymenolepid cestode Branchiopodataenia arctowskii (Jarecka & Ostas, 1984), for which B. gaini is an intermediate host (Jarecka 1984 ). Definitive hosts are seagulls, which consume infected crustaceans. This parasite is not endemic to Antarctica, as it meet in the Northern Hemisphere too (Bondarenko and Kontrymavicius 2004). Unfortunately, there is no information on the infection of B. gaini populations by this or other parasites in the region of the Wilhelm Archipelago. However, the facts of the South Polar Skua feeding on this crustacean and the presence of the migrating species the Kelp Gull ( Larus dominicanus Lichtenstein, 1823) may indicate the potential presence of this parasite in the crustaceans of this Antarctic region and its possible impact on local anostracan populations; 3) Representatives of B. gaini are able to enter into a symbiotic relationship with microorganisms. Scientists studied the formation of phyllosymbiosis and the impact on the existence of this type of microbiome that forms on the gills and in the intestines of crustaceans. Microbiomes are assembled through different ecoevolutionary processes stochastically in the gills and deterministically in the gut in each anostracans population. A strong correlation was found between the genetic makeup of B. gaini and its gut and gill microbiome (Schwob et al. 2024 ). Such symbioses, which are formed as a result of the anostracan interaction with the external environment, can potentially have a positive effect on the survival of sexually mature specimens in an aggressive environment; 4) Branchinecta gaini is able to exist in reservoirs of different trophic levels. In our research, this species was found in oligotrophic L1 on Uruguay Island, in a number of mesotrophic ponds and rock pools, in eutrophic RP18 on Petermann Island. It is worth noting that this specie was found even in freshwater bodies with a large amount of decomposed and semi-decomposed moss at the bottom (for example, RP14 on Maly Berthelot Island). The main thing is that the free space of the water above the moss remains. This is confirmed by the results of the Mann-Whitney-Wilcoxon test. It indicates that representatives of this species were found more often at a greater depth on average. In general, there are only a few eutrophic reservoirs with the presence of these crustaceans, and they predominate in mesotrophic reservoirs. On the other hand, researchers discovered anostracans in Pond №VII on King George Island in 1977–1978. This pond is located near a large colony of penguins and their waste products entering the water, it causes eutrophication of the reservoir. As a result of the presence of a large amount of organic matter and the massive development of microalgae, the representatives of the B. gaini of this reservoir have acquired gigantic sizes. Thus, the maximum body length of females was 28.1 mm, and males – 29.8 mm (Jurasz et al. 1983 ). This is despite the fact that the standard size of representatives of this species corresponds to 16 mm (Hawes 2009 ). However, the amount of organic matter in the water should not exceed threshold values, since B. gaini is absent in hypertrophic reservoirs. No crustaceans were found in water bodies with a huge amount of guano during our research on Moot Island (Fig. 15 a). And although only one sample from the pond was examined in laboratory conditions (Fig. 15 b), water was examined in the place for the presence of large-sized crustaceans from more than 10 rock pools located around it (Fig. 15 c–e); 5) Branchinecta gaini has a wide range of nutrition and flexible eating behavior. It is characterized by the behavior of scraping off organic matter and transferring it to the oral apparatus with the help of complex manipulations of body appendages. This anostracan can grab pieces of detritus on the bottom half the size of their body and then swim belly up, destroying the detritus with their limbs and manipulating its parts (Hawes 2008 ). However, this species is not a narrow detritophagus. The contents of his intestines include the remains of organic sediments and benthic biota was found. Its diet contains a large amount of algae and cyanobacterial mat, which it scrapes from the walls of freshwater reservoirs. Hyphae and spores of fungi, protists, rotifers, tardigrades, parts of the legs of mites, and chironomids, as well as the remains of B. poppei and B. gaini , were also found. Thus, B. gaini is a detritophagous and filter-feeding herbivore that feeds mainly near the bottom on detritus and benthic biota (Paggi 1996 ). In addition, it is capable of cannibalizing its own dead individuals. Accordingly, it contribute to its own detritus food web, dying before Antarctic winter and providing a food base for the next generation during the following Antarctic summer (Hawes 2008 ). It is suggested that B. gaini may also prey on B. poppei larvaes (Pociecha and Dumont 2008 ). We observed classic feeding of B. gaini in P11 on Petermann Island. Transparent water made it possible to visually monitor nutrition. Most of the individuals stayed near the walls and bottom of the reservoir, scraping the cyanobacterial mat and bottom benthos groups from the stones. A few individuals swam belly up with large particles of detritus (pieces of decomposed moss), destroying it with body appendages and directing the detached particles to the mouth apparatus. However, several other individuals swam belly up in the stratum and near the water surface without detritus. They actively moved their limbs and created a flow of water to the front of the body. Therefore, we can make an assumption that they filtered water with suspended organic matter, that is, they fed as planktonic filter feeders. A similar phenomenon was observed in L1 of the Uruguay Island; 6) The survival of B. gaini in the extreme conditions of the Antarctic is facilitated by the peculiarities of its univoltine life cycle, when only one generation exists during the year. Adaptation to living conditions consists in shortening the development time of active stages and the formation of resting eggs in the difficult conditions of the Antarctic winter. An analysis of the life cycle was conducted on the example of the population of this species from King George Island. Nauplius larvae hatch from resting eggs in November, metanauplius larvae and young individuals develop from them. Development from egg to adult takes place within a month, that is, the first adults appeared in December, and the reproductive period began in January. They laid eggs until mid-May under the ice and died, the reproductive period lasted from January until the water bodies froze. Thus, the active phase of the life cycle lasted from November to May, about six months, and for another six months it experienced adverse conditions in the egg stage. The latter are resistant to low temperatures, lack of oxygen and exposure to ultraviolet radiation, which allows them to survive in freezing water conditions (Jurasz et al. 1983 ). The time and features of the life cycle of B. gaini can vary according to changes in habitat conditions. Our studies have shown that in the harsher southern conditions of the Wilhelm Archipelago area, the active phase of the B. gaini life cycle is even more shortened. The period of the beginning of the formation of adults was not in December, but in January, since in December the reservoirs were still covered with ice and in February larvae and juveniles were found in a number of reservoirs next to sexually mature individuals (L1 on Uruguay Island, P8 on Irizar Island, P11 on Petermann Island, etc.). At the same time, freshwater reservoirs began to be covered with ice at the end of March 2020, and already at the beginning of April, the number of living individuals decreased (L1 on Uruguay Island). Thus, the active phase of the life cycle was reduced from 6 months to 4–5 months. However, the flexibility of the life cycle allowed it to survive in these changing extreme conditions. An interesting feature is that in L1, juveniles prevailed over adults in March 2020. This can be explained by the fact that females lay eggs at different times and eggs laid in a shallow part of the reservoir and subjected to freezing could hatch prematurely, in the year of their laying. This is confirmed by the data of other scientists (Jurasz et al. 1983 ); 7) A key factor to the mastery of B. gaini in the Antarctic region is the presence of unique eggs that are capable of cryptobiosis and tolerate freezing conditions during the Antarctic winter (Fryer 1996 ). These eggs are double-shelled (Jurasz et al. 1983 ) and survive freezing to -25°C and desiccation (Peck 2004 ). As a result of mass lying of eggs, their banks are formed, which ensure their mass hatching and distribution. Eggs hatch at positive temperatures, sufficient oxygen concentration in the water and the presence of light (Brendonck 1996 ). Thus, it is the peculiarities of the organization of the eggs that allow this species to survive during freezing water. The eggs can spread with the help of vectors and take over new freshwater bodies. After hatching, these crustaceans quickly develop from larvae to adults, which reproduce and form new egg banks. In our opinion, an important factor in the formation of large egg banks of B. gaini in small freshwater bodies is the formation of large concentrations of adults of this crustacean due to the gradual drying up of small reservoirs and lowering of their water level. We observed a similar phenomenon in RP11 on Grotto Island and in several freshwater bodies in the Palmer Station area (the region of Anvers Island) in 2020; 8) Branchinecta gaini is characterized by significant morphological and physiological variability between different populations (Pandourski and Evtimova 2009 ) and between different sexes (Jurasz et al. 1983 ; Pociecha 2007 ). Variability contributes to the heterogeneity of a species, which can favor the survival of populations with a particular set of traits in a variable habitat; 9) Finally, the anthropogenic factor increasingly affects the existence and distribution of B. gaini in freshwater bodies of the Antarctic. For example, plastic pollution of the Maritime Antarctic is gaining momentum. At the same time, both individual species and entire ecosystems suffer from pollution. Branchinecta gaini was studied for the effect of nanoplastics on them. Studies have shown that nanoplastic affects the growth rate of anostracan molting, changes in the intestinal epithelium, rate of ventilation, and regulation of body functions. The changes occurred at the behavioral and molecular levels. As a result, the researchers concluded that nanoplastics pose a threat to Antarctic biodiversity, and B. gaini can be used as a model to assess the impact of pollutants on freshwater ecosystems (Bergami et al. 2022 ). Branchinecta gaini has also been proposed as a biomonitor in the Antarctic due to its sensitivity to nanosized titanium dioxide (n-TiO2). It is a widely used pigment that is present, for example, in paintings and sunscreens (González-Aravena et al. 2022 ). It is believed that it can also be a bioindicator of oligotrophic ponds (De Los Rios et al. 2008). Third, the species must have mechanisms of distribution. Therefore, we will consider the main from them for anostracans to freshwater reservoirs of new territories. There are two main distribution strategies (Jocqué et al. 2010 ): active dispersers – able to independently move from one habitat into new habitats; passive dispersers – need help to move from one habitat into new habitats. Branchinecta gaini belongs to passive dispersers, since its representatives are not able to actively move in sea water, on land or by air from one freshwater body to another. Passive disperser in the Antarctic is an accidental phenomenon, since B. gaini entered this continent by random zoophoretic dispersal of eggs by means birds. Similar dispersal by eggs is common in many anostracans (Brendonck 1996 ). Four vectors of passive dispersers can be considered in the Antarctic ecosystems (Hawes 2009 ): anthrochory, hydrochory, anemochory, and zoochory. Next, we will consider the main vectors of the spread of B. gaini into new Antarctic freshwater bodies: 1) Anthrochory is the dispersal of passive dispersers directly by a person or indirectly with his participation. Although scientists deny this vector of B. gaini egg transfer (Hawes 2009 ), we will try to express a hypothesis based on personal observations. Over the past decades, there has been an increase in the number of tourists visiting the region of the Wilhelm Archipelago. They have tourist routes, with landings from ships on islands, mostly with penguin colonies and beautiful landscapes. The base point in this region is Petermann Island, through which thousands of tourists pass every year. In the area where the tourist routes pass, there is at least RP18 with anostracans. Potentially, tourists can wash their boots in a pond with crustaceans from the penguin guano, and the bottom sediments are stay on the soles of the shoes. And then everything will depend on the stickiness of the mud. Then the remains of mud with eggs will not be washed from the boots when walking on snow if the stickiness is high. And a person can wash his boots before getting into the boat again and the eggs can get into another freshwater body. Thus, eggs can be transferred from one reservoir to another within one island. Tourists wash their boots on the ship, so further transfer is unlikely. However, tourists often go from one island to another without boarding a ship, for example, from Petermann Island to Great Yalour Island. There is a large colony of other species of penguin. And there can be several such points and at each point people want wash their boots before getting into the boat. If you take tourists on yachts, they land on even more surrounding islands and the probability of accidental contamination is high. The same can be said for inexperienced scientists from different countries, as potentially not all of them thoroughly wash their boots in seawater before getting into the boat. Therefore, in our opinion, the probability of transferring B. gaini eggs from one freshwater body to another within one island and between different islands is quite high. But this hypothesis needs practical proof; 2) Hydrochory is the dispersal of passive dispersers directly by water. Branchinecta gaini can stochastic spread by water into freshwater bodies for short distances within one island. This is due to the fact that the reservoirs of this region Antarctic are mostly not connected to each other in a single system. Cascades of bodies of water flowing into each other are registered on Irizar, Eight, and Maly Berthelot Islands. Most of the isolated reservoirs are located in crevices on the slopes of hills or on terraces, and water in them can flow into each other only during the melting of snow and ice. This may be facilitated by the ability of eggs to float to the surface if they are not silted to the bottom of the reservoir (Brendonck and Riddoch 1999 ). Thus, B. gaini eggs can disperse with the help of water, but not over long distances within a limited area of ​​land. 3) Anemochory is the dispersal of passive dispersers directly by air. Anostracans eggs can be stochastically dispersed by air over short distances between freshwater bodies (Brendonck and Riddoch 1999 ). The spread of eggs over long distances by air is considered unlikely (Vanschoenwinkel et al. 2008 ). This type of dispersal is possible only within shallow rock pools that have time to dry out during the short Antarctic summer. Accordingly, dried sludge with B. gaini eggs can be carried by the wind over short distances into nearby freshwater bodies. A similar type of distribution could occur, for example, between the reservoirs of Maly Berthelot Island; 4) Zoochory is the dispersal of passive dispersers directly by animals. Branchinecta gaini can be directed from one reservoir to another over short and long distances by birds (Diaz et al. 2019). It is directional, as a number of waterfowl settle and concentrate near freshwater bodies that are indispensable for birds to drink, bathe, rest, and feed (Viana et al. 2013 ). The South Polar Skua, Kelp Gull, Antarctic Tern ( Sterna vittata Gmelin, 1789), and Snowy Sheathbill ( Chionis albus (Gmelin, 1789)) can potentially move B. gaini eggs in this region of the Wilhelm Archipelago. We only observed the South Polar Skua consuming B. gaini . Potentially all of these species may consume anostracans, although they do not make up a significant proportion of their diet. This is confirmed by the data of other researchers, for example, they note the consumption of these crustaceans by the Antarctic Tern and South Polar Skua (Nedbalová et al. 2017 ). Zoochory can manifest itself through epizoochory and endozoochory (Hawes 2009 ). Epizoochory is a type of zoochory, when the dispersal of passive dispersers directly by transfer on the surface of the animal body. Branchinecta gaini eggs can stick to the feet and feathers of birds along with mud when the latter bathe, drink water or fed. A similar type of distribution is characteristic of other crustaceans (Trokhymets et al. 2024 ). It can occur both between neighboring reservoirs and over long distances between islands. A similar distribution is highly likely for most freshwater bodies, as the South Polar Skua and other birds nest and inhabit almost all islands in the Wilhelm Archipelago area. They fly long distances to other groups of islands and the continental coast during hunting. We watched the South Polar Skua fly from Locator Island towards Galindez Island for a distance of about 13 km and then return within a few hours. Endozoochory is a type of zoochory, when the dispersal of passive dispersers directly by transfer inside the animal's digestive system. Similar transportation of anostracans eggs occurs by accidental ingestion of them into the digestive system of animals while drinking water or by targeted consumption of female crustaceans with viable eggs. Thus, eggs can be safely transported in the digestive system of birds during long-distance flights and, after bird excretion, enter new freshwater bodies (Green and Figuerola 2005 ; Rogers 2014 ). In other regions of the planet, insects (Beladjal and Mertens 2009 ), fish (Beladjal et al. 2007 ), amphibians (Bohonak and Whiteman 1999 ), and birds (Green et al. 2005 ) are capable of carrying anostracans eggs in the digestive system. However, most of the predators capable of hunting anostracans in the Antarctic are absent. Therefore, only birds can carry B. gaini eggs in their own digestive system. We have already provided a list of bird species potentially capable of spreading anostracans eggs by zoochory. Other scientists also identify some of these birds as possible vectors for the spread of this crustacean species (Hawes 2009 ; Nedbalová et al. 2017 ). Thus, endozoochory (as well as epizoochory) is one of the main ways of spreading B. gaini over short and long distances within the Wilhelm Archipelago. As a result of our research, we can conclude that B. gaini is found in reservoirs with cyanobacterial mats on the walls and detritus on the bottom, it need water space (it were also found at a depth of 0.1 m, but they preferred reservoirs with a greater depth), the presence of birds for zoochory, but absent around large penguin colonies. As for distribution in the Wilhelm Archipelago region, this species has a wide range of vectors, but the most common variants are zoochory and hydrochory. Declarations Acknowledgements The authors express their gratitude to the National Antarctic Scientific Center of Ukraine (Ministry of Education and Science of Ukraine) for funding and organizing the Ukrainian Antarctic Expeditions, during which collection and analysis of specimens were conducted. We are also grateful to the Taras Shevchenko National University of Kyiv for fully supporting this study. The authors acknowledge Natural Earth, SCAR (Antarctic Digital Database) and UK Polar Data Centre for providing access to map databases for non-commercial use. We would like to dedicate this article to the Ukrainian people. Author contributions VT conceived the study; VT, PDLRE, AZ, and ID wrote the manuscript; VT and ID conducted field and lab work. 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Contrasted diversity patterns and eco-evolutionary processes between gill and intestinal microbiomes of Antarctic fairy shrimps. Front Ecol Evol 12:1438057. https://doi.org/10.3389/fevo.2024.1438057 Toro M, Camacho A, Rochera C, Rico E, Bañón M, Fernández-Valiente E, Marco E, Justel A, Avendaño MC, Ariosa Y, Vincent WF, Quesada A (2006) Limnological characteristics of the freshwater ecosystems of Byers Peninsula, Livingston Island, in maritime Antarctica. Polar Biol 30(5):635–649. https://doi.org/10.1007/s00300-006-0223-5 Trokhymets V, Dykyy I (2021) Freshwater crustaceans in the area of Argentine Islands (Wilhelm’s Archipelago, West Antarctica). Materials of the second Kharkiv Conference on invertebrate zoology, Ukraine (in Ukrainian) Trokhymets V, Gorobchyshyn V, Kozeretska I (2021) Population features of Boeckella poppei in Lake Wujka, King George Island. UAJ 1:117–122. https://doi.org/10.33275/1727-7485.1.2021.670 Trokhymets V, Savytskiy O, Zinkovskyi A, Gupalo O, Dykyy I, Lutsenko D, Berezkina A, Mario LM (2022) Species composition, distribution and relative abundance of the inshore fish community off the Argentine Islands, Bellingshausen Sea. Polar Biol 45:845–855. https://doi.org/10.1007/s00300-022-03040-5 Trokhymets V, Zinkovskyi A, Dykyy I (2024) Distribution of Boeckella poppei (Copepoda: Centropagidae) in the region of the Wilhelm Archipelago (Kyiv Peninsula, Maritime Antarctica). Polar Biol 47:349–365. https://doi.org/10.1007/s00300-024-03238-9 Vanschoenwinkel B, Gielen S, Seaman M, Brendonck L (2008) Any way the wind blows - frequent wind dispersal drives species sorting in ephemeral communities. Oikos 117:125–134. https://doi.org/10.1111/j.2007.0030-1299.16349.x Viana DS, Santamaría L, Michot TC, Figuerola J (2013) Migratory strategies of waterbirds shape the continental-scale dispersal of aquatic organisms. Ecography 36(4):430–438. https://doi.org/10.1111/j.1600-0587.2012.07588.x Weller MW (1975) Notes on formation and life of ponds of the Falkland Islands and South Georgia. Br Antarct Surv Bull 40:37–47 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6255807","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":441994323,"identity":"9b15592c-ecff-4022-a922-5f42b38cd60c","order_by":0,"name":"Vladlen Trokhymets","email":"","orcid":"","institution":"Taras Shevchenko National University of Kyiv","correspondingAuthor":false,"prefix":"","firstName":"Vladlen","middleName":"","lastName":"Trokhymets","suffix":""},{"id":441994324,"identity":"8229321b-809f-4dc3-9f06-8b4865bd83db","order_by":1,"name":"Ihor Dykyy","email":"","orcid":"","institution":"Ivan Franko National University of Lviv","correspondingAuthor":false,"prefix":"","firstName":"Ihor","middleName":"","lastName":"Dykyy","suffix":""},{"id":441994325,"identity":"0bc1d7f7-08d0-44ff-b5d8-dbe092b9d3e5","order_by":2,"name":"Artem Zinkovskyi","email":"","orcid":"","institution":"Holosiivsky Lyceum №241","correspondingAuthor":false,"prefix":"","firstName":"Artem","middleName":"","lastName":"Zinkovskyi","suffix":""},{"id":441994326,"identity":"42846239-9760-46da-b70b-cc931c45d547","order_by":3,"name":"Patricio R. De los Rios-Escalante","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAkUlEQVRIiWNgGAWjYFACxgYGhgoI6wAJWs4wMPAAmcRqAelqI0WLufThxoc/5x2Wt2dgfkCcFsu+xGZj3m2HDXsY2AyI02JwhrFNmnHb4QQeoNOI1yL5cw6pWiR4G0jRYtnD2GzMcyzdsOcwsX4x52F/+PBHjbU8e3vzwwfEOQzOYiZKPYqWUTAKRsEoGAW4AACS6irpK1LefgAAAABJRU5ErkJggg==","orcid":"","institution":"Universidad Católica de Temuco","correspondingAuthor":true,"prefix":"","firstName":"Patricio","middleName":"R. De los","lastName":"Rios-Escalante","suffix":""}],"badges":[],"createdAt":"2025-03-18 19:08:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6255807/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6255807/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":81149497,"identity":"3c906503-a256-49db-9518-d93d7c5e64a0","added_by":"auto","created_at":"2025-04-22 19:17:08","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":76959,"visible":true,"origin":"","legend":"\u003cp\u003eGeographic distribution of \u003cem\u003eBranchinecta gaini\u003c/em\u003ewithin the Southern Hemisphere. 1 – South Georgia, 2 – South Orkney Islands, 3 – South Shetland Islands, 4 – Antarctic Peninsula (mostly in the area of ​​the west coast from James Ross Island to Marguerite Bay), 5 – Falkland Islands (* – it is necessary to carry out re-identification to clarify the species belonging to the finds)\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/c0e2b683bce7802353ca115c.jpg"},{"id":81149500,"identity":"8aade90d-d56b-4690-8e46-c09e1fdf750f","added_by":"auto","created_at":"2025-04-22 19:17:08","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":86615,"visible":true,"origin":"","legend":"\u003cp\u003eDifferent stages of \u003cem\u003eBranchinecta gaini \u003c/em\u003edevelopment. \u003cstrong\u003ea-b\u003c/strong\u003e – male, \u003cstrong\u003ec\u003c/strong\u003e – female, \u003cstrong\u003ed\u003c/strong\u003e – eggs, \u003cstrong\u003ee\u003c/strong\u003e – larvae\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/8447faf0a0bde6c6d026ce04.jpg"},{"id":81149498,"identity":"ab80ab96-50b8-4780-9215-0bc4150fd91f","added_by":"auto","created_at":"2025-04-22 19:17:08","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":82118,"visible":true,"origin":"","legend":"\u003cp\u003eDistribution of \u003cem\u003eBranchinecta gaini\u003c/em\u003e in the study area.1 – Uruguay Is., 2 – Galindez Is., 3 – Skua Is., 4 – Mitina Is., 5 – Berthelot Is., 6 – Petermann Is., 7 – Winter Is., 8 – Irizar Is., 9 – Eight Is., 10 – Grotto Is., 11 – Maly Berthelot Is., 12 – Black Is.; x – missing\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/93d29b09781a9a73e2dc25c9.jpg"},{"id":81149503,"identity":"dbf6ab1e-584c-4261-a7ef-5edb9b2281a2","added_by":"auto","created_at":"2025-04-22 19:17:08","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":158947,"visible":true,"origin":"","legend":"\u003cp\u003eUruguay Island and its freshwater bodies with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea\u003c/strong\u003e– topographic map of Uruguay Is., \u003cstrong\u003eb\u003c/strong\u003e – photo of the Pond 1, \u003cstrong\u003ec\u003c/strong\u003e– photo of the Pond 9, \u003cstrong\u003ed – \u003c/strong\u003ephoto of the bottom of Lake 1, \u003cstrong\u003ee\u003c/strong\u003e – photo of the Lake 1; 1 – Pond 1, 2 – Pond 9, 3 – Lake 1 (* – the “Basic freshwater hydrobiological station №1” for permanent monitoring of hydrobionts and the Base station №2 for long-term monitoring of \u003cem\u003eB. gaini\u003c/em\u003e and \u003cem\u003eBoeckella poppei\u003c/em\u003e)\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/daf816f09e42e8c823db0ba4.jpg"},{"id":81149889,"identity":"9ad55ab5-2e99-4100-9be6-b14d2874fcc8","added_by":"auto","created_at":"2025-04-22 19:25:08","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":79611,"visible":true,"origin":"","legend":"\u003cp\u003eGalindez Island and its freshwater bodies with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea\u003c/strong\u003e – topographic map of Galindez Is., \u003cstrong\u003eb\u003c/strong\u003e – photo of the Pond 2, \u003cstrong\u003ec\u003c/strong\u003e – photo of the bottom of Pond 2; 1 – Pond 1 (* – the Base station № 3 for long-term monitoring of \u003cem\u003eB. gaini\u003c/em\u003e), 2 – Rock pool 19; ** – the Base station № 3 for long-term monitoring of \u003cem\u003eBoeckella poppei\u003c/em\u003e\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/5838187846976b8ee979b95f.jpg"},{"id":81149892,"identity":"a0d59118-2d99-48b8-97cb-2feb73df5784","added_by":"auto","created_at":"2025-04-22 19:25:08","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":177345,"visible":true,"origin":"","legend":"\u003cp\u003eSkua Island and its freshwater body with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea\u003c/strong\u003e – topographic map of Skua Is., \u003cstrong\u003eb\u003c/strong\u003e – photo of the bottom of Rock pool 1 with \u003cem\u003eB. gaini\u003c/em\u003e representatives, \u003cstrong\u003ec\u003c/strong\u003e– photo of the largest freshwater body of Skua Is.; 1 – Rock pool 1; * – the “Basic freshwater hydrobiological station №2”\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/05b095a4eecfbfb622f3be0a.jpg"},{"id":81149505,"identity":"535d473e-473f-420a-a580-17c177db769f","added_by":"auto","created_at":"2025-04-22 19:17:08","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":153553,"visible":true,"origin":"","legend":"\u003cp\u003eMitina Island its freshwater body with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea\u003c/strong\u003e – topographic map of The\u003cstrong\u003e \u003c/strong\u003eBarchans, \u003cstrong\u003eb\u003c/strong\u003e – photo of the Pond 3; 1 – Pond 3\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/b1a283bc8b2efff12c32caa9.jpg"},{"id":81150213,"identity":"89c64e52-e387-4952-a97a-2453bf370f76","added_by":"auto","created_at":"2025-04-22 19:33:08","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":213470,"visible":true,"origin":"","legend":"\u003cp\u003eBerthelot and Maly Berthelot Islands, and its freshwater bodies with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea \u003c/strong\u003e– topographic map of Berthelot Is., \u003cstrong\u003eb–c\u003c/strong\u003e – photos of the Pond 4, \u003cstrong\u003ed\u003c/strong\u003e – photo of the Pond 10; 1 – Pond 4, 2 – Pond 10, 3 – Rock pool 14, 4 – Rock pool 15, 5 – Rock pool 16, 6 – Rock pool 17\u003c/p\u003e","description":"","filename":"8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/15c2ab73344089c20329c72a.jpg"},{"id":81149890,"identity":"8c14f2b0-7a92-4a5d-84ca-3f335bdd5410","added_by":"auto","created_at":"2025-04-22 19:25:08","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":227054,"visible":true,"origin":"","legend":"\u003cp\u003ePetermann Island and its freshwater bodies with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea\u003c/strong\u003e– topographic map of Petermann Is., \u003cstrong\u003eb\u003c/strong\u003e – photo of the Pond 5, \u003cstrong\u003ec\u003c/strong\u003e – photo of the bottom of Pond 5,\u003cstrong\u003e d\u003c/strong\u003e– photo of the Rock pool 18, \u003cstrong\u003ee\u003c/strong\u003e – photo of the Pond 11; 1 – Pond 5, 2 – Rock pool 18, 3 – Pond 11\u003c/p\u003e","description":"","filename":"9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/da031158a3756b8bfbfbfee3.jpg"},{"id":81149519,"identity":"497ea9fc-b944-4d99-8f4b-69a1568ffb12","added_by":"auto","created_at":"2025-04-22 19:17:09","extension":"jpg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":88187,"visible":true,"origin":"","legend":"\u003cp\u003eWinter Island and its freshwater body with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea\u003c/strong\u003e – topographic map of Winter Is., \u003cstrong\u003eb\u003c/strong\u003e – photo of the Rock pool 2; 1 – Rock pool 2\u003c/p\u003e","description":"","filename":"10.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/6916d0096289a80269d1cc45.jpg"},{"id":81150214,"identity":"4e5951a2-b87c-4483-b9b6-5470a3bf90ad","added_by":"auto","created_at":"2025-04-22 19:33:08","extension":"jpg","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":206769,"visible":true,"origin":"","legend":"\u003cp\u003eIrizar Island and its freshwater bodies with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea\u003c/strong\u003e– topographic map of Irizar Is., \u003cstrong\u003eb \u003c/strong\u003e– photo of the Pond 6, \u003cstrong\u003ec\u003c/strong\u003e – photo of the Rock pools 4–5, \u003cstrong\u003ed\u003c/strong\u003e – photo of the Pond 8; 1 – Pond 6 (* – the Base station №1 for long-term monitoring of \u003cem\u003eB. gaini\u003c/em\u003e and \u003cem\u003eBoeckella poppei\u003c/em\u003e), 2 – Rock pool 3, 3 – Rock pool 4, 4 – Rock pool 5, 5 – Pond 7, 6 – Pond 8, 7 – Rock pool 6\u003c/p\u003e","description":"","filename":"11.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/2a74ae9f5d0ac5b1d5fb4500.jpg"},{"id":81149510,"identity":"0d53e270-5d23-478e-976c-8ee03c145807","added_by":"auto","created_at":"2025-04-22 19:17:08","extension":"jpg","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":250732,"visible":true,"origin":"","legend":"\u003cp\u003eEight Island and its freshwater bodies with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea\u003c/strong\u003e– topographic map of Eight Is., \u003cstrong\u003eb \u003c/strong\u003e– photo of the Rock pool 7, \u003cstrong\u003ec\u003c/strong\u003e – photo of the Rock pool 8; 1 – Rock pool 7, 2 – Rock pool 8, 3 – Rock pool 9, 4 – Rock pool 10\u003c/p\u003e","description":"","filename":"12.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/9bc7606d5512d82e190e4b53.jpg"},{"id":81149514,"identity":"d8103afe-57a0-4706-9a24-86b2b8990fd7","added_by":"auto","created_at":"2025-04-22 19:17:09","extension":"jpg","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":216956,"visible":true,"origin":"","legend":"\u003cp\u003eGrotto Island and its freshwater bodies with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea\u003c/strong\u003e– topographic map of Grotto Is., \u003cstrong\u003eb\u003c/strong\u003e – photo of the Rock pool 11, \u003cstrong\u003ec\u003c/strong\u003e– photo of the bottom of Rock pool 12; 1 – Rock pool 11, 2 – Rock pool 12, 3 – Rock pool 13\u003c/p\u003e","description":"","filename":"13.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/9409533c27573ea8162045eb.jpg"},{"id":81149520,"identity":"7a59a4dc-a483-4864-b3df-1e54a2c8f997","added_by":"auto","created_at":"2025-04-22 19:17:09","extension":"jpg","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":74115,"visible":true,"origin":"","legend":"\u003cp\u003eBlack Island and its freshwater body with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea\u003c/strong\u003e – topographic map of Black Is., \u003cstrong\u003eb\u003c/strong\u003e – photo of the bottom of Pond 12; 1 – Pond 12\u003c/p\u003e","description":"","filename":"14.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/0ed3f28d54fa4fc002a35413.jpg"},{"id":81149897,"identity":"835b3947-3cf4-4829-9336-bb7b6cbded1e","added_by":"auto","created_at":"2025-04-22 19:25:09","extension":"jpg","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":229754,"visible":true,"origin":"","legend":"\u003cp\u003eMoot Island and its freshwater reservoirs with pronounced organic pollution by the products of the life activities of the penguin colony. \u003cstrong\u003ea\u003c/strong\u003e – topographic map of Moot Is., \u003cstrong\u003eb–e\u003c/strong\u003e – photos of the freshwater bodies near the penguin colony; 1 – large polluted pond, around which other polluted freshwater bodies are located\u003c/p\u003e","description":"","filename":"15.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/d6dc9b026fa16b6eaa33fa37.jpg"},{"id":89591866,"identity":"d13fe9ce-7529-4e4c-8f1b-4baebe37146d","added_by":"auto","created_at":"2025-08-21 16:09:06","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3763931,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6255807/v1/07e9e563-e671-4297-8035-8c0ab11b1671.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Distribution and its mechanisms of Branchinecta gaini (Branchiopoda: Anostraca) in the area of the Wilhelm Archipelago (Maritime Antarctica)","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAntarctica is characterized by unique and extreme conditions for the existence of living organisms. They are especially complex within terrestrial ecosystems (Convey \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). This is due to the fact that daily and seasonal fluctuations in indicators of various environmental factors (for example, temperature) within terrestrial ecosystems are high. Instead, these indicators are more stable in the marine environment of the Antarctic. Therefore, the biota of terrestrial ecosystems should be characterized by high physiological and ecological flexibility in relation to changes in environmental factors (Peck \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Aboriginal biota has adapted to exist in such harsh conditions over millions of years. However, modern changes in the environment caused by high rates of warming can lead to an increase in the size of species areal, quantitative indicators of populations, productivity, complexity of communities, as well as the penetration of new species into the Antarctic territory (Convey and Peck \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Bargagli \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eA special place in terrestrial ecosystems is occupied by permanent and temporary freshwater reservoirs (lakes, ponds, rock pools). The most quantitatively represented are small water bodies, among which rock pools predominate (Hawes et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). The latter are among the oldest and most extreme temporary habitats (Brendonck and Riddoch \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1999\u003c/span\u003e). The biota of these freshwater bodies on the territory of different continents includes about 460 species of animals. Antarctic rock pools are characterized by the highest rates of species diversity of fauna compared to other continents, which is associated with the development of specific adaptations to extreme habitat conditions. Antarctic animals with the strategy of active dispersers are represented by 42 genera, and with the strategy of passive dispersers \u0026ndash; 41 genera. For comparison, animals with corresponding strategies are represented in rock pools of North America by 32 and 14 genera (Jocqu\u0026eacute; et al. \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2010\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe basis of biodiversity and biomass of different taxonomic groups of Antarctic freshwater bodies\u0026rsquo; biota is formed by cyanobacteria and plants, and their stability is determined by animals. Benthos and plankton predominate in the life forms to which representatives of various taxonomic groups may belong. The benthos forms the basis of the biodiversity and biomass of freshwater bodies, and the plankton provides their stability (Gibson et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). In total, 336 taxa (defined to species, genera, and higher-level taxa) of invertebrate animals have been registered in various types of Antarctic freshwater bodies. Of these, 121 taxa are known for the waters of Maritime Antarctica (Dartnall \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Crustaceans play an important role as first- and second-order consumers (Pugh et al. \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). They are represented by 66 taxa, nine of which were found in the Maritime Antarctic. Just four species of crustaceans have been registered in freshwater bodies of the Antarctic Peninsula: two species of branchiopods and two copepods (Diaz et al. 2019; Trokhymets et al. \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eToday, about 500 species belong to the Class Branchiopoda Latreille, 1817. Several taxonomic groups are distinguished within the class: fairy shrimps (Order Anostraca Sars, 1867), clam shrimps and cladocerans (Superorder Diplostraca Latreille, 1829), and tadpole shrimps (Order Notostraca Sars, 1867). Anostracans live mainly in temporary freshwater bodies, although marine species are also found among them. The vast majority of these crustaceans belong to omnivorous filter feeders, although predators are also found among them (Brendonck et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Adverse conditions are tolerated by the formation of resting egg (\"cysts\") banks in the water (Brendonck \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1996\u003c/span\u003e). Anostracans are large branchiopods, but in recent decades many new species have been described within different regions of the planet (Rogers and Ferreira \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Lazo-Wasem and Hegna \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Thus, these crustaceans numbered 258 species in 1993 (Belk and Brtek \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1995\u003c/span\u003e), and they numbered about 300 species already in 2008 (Brendonck et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). This can be explained by the fact that almost 25% of these species are known only from typical localities (Belk and Brtek \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1995\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cem\u003eBranchinecta\u003c/em\u003e Verrill 1869 from the family Branchinectidae Daday, 1910 is the only genus of anostracans whose representatives live in Antarctic freshwater bodies. This genus includes about 48 species, distributed in water bodies on most continents except Africa and Australia (Evtimova et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Rogers et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2020b\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAntarctic Fairy Shrimp (\u003cem\u003eBranchinecta gaini\u003c/em\u003e Daday, 1910) is the only anostracan species present in Antarctic freshwater bodies (Rosenfeld et al. \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). For the first time, this species was found on Petermann Island (65\u0026deg;10\u0026deg;34\"S 66\u0026deg;32'30\"W) and small islands located near it in the area of ​​the Wilhelm Archipelago (Maritime Antarctica) during the Second French Antarctic Expedition with led of Jean-Baptiste Charcot by Mr. L. Hein in 1909 (Dabay De De\u0026eacute;s 1910). Until recently, representatives of this species were believed to be widespread in freshwater bodies of southern South America (De Los Rios et al. 2008; Rogers et al. \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; De Los R\u0026iacute;os-Escalante and Kotov \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), Falkland Islands (Weller \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e1975\u003c/span\u003e; Hawes \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Diaz et al. 2019), South Georgia (Dartnall and Heywood \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e1980\u003c/span\u003e; Dartnall \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Dartnall \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), South Orkney Islands (Brendonck et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Dartnall \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Diaz et al. 2019), South Shetland Islands (Janiec \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Toro et al. \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Rochera and Camacho \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), and Antarctic Peninsula (Bj\u0026ouml;rck et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Nedbalova et al. 2017). According to this approach, \u003cem\u003eB. gaini\u003c/em\u003e coexisted in Patagonia with the very morphologically similar species \u003cem\u003eBranchinecta granulosa\u003c/em\u003e Daday, 1902 (Linder \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e1941\u003c/span\u003e; Rogers et al. \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). In addition, a number of sources noted records of \u003cem\u003eB. granulosa\u003c/em\u003e in freshwater bodies of the Antarctic (Bryant \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1945\u003c/span\u003e; Polishuk et al. \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). However, most scientists disputed this possibility and believed that these were misidentifications of \u003cem\u003eB. gaini\u003c/em\u003e (Pugh et al. \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Hawes \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Rogers et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2020a\u003c/span\u003e). The existence of \u003cem\u003eB. gaini\u003c/em\u003e in southern South America and the Falkland Islands has long been questioned (Pugh et al. \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Rogers et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2020a\u003c/span\u003e). Shortly after, Rogers et al. (\u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2020b\u003c/span\u003e) concluded that all Patagonian finds of \u003cem\u003eB. gaini\u003c/em\u003e actually belong to \u003cem\u003eB. granulosa\u003c/em\u003e and that the distribution of \u003cem\u003eB. gaini\u003c/em\u003e is restricted to Antarctica and adjacent islands. Comparative molecular genetics and phylogenetic analyzes of \u003cem\u003eB. granulosa\u003c/em\u003e and \u003cem\u003eB. gaini\u003c/em\u003e were carried out in 2024. The analysis revealed insufficient genetic differentiation between the two species, suggesting the existence of a single species with small morphological differences between its populations within different areas of its areal (Pokorn\u0026yacute; et al. \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Therefore, there are two main approaches to the distribution of \u003cem\u003eB. gaini\u003c/em\u003e, based on the modern revision within the genus \u003cem\u003eBranchinecta\u003c/em\u003e: 1) \u003cem\u003eB. granulosa\u003c/em\u003e and \u003cem\u003eB. gaini\u003c/em\u003e are separate species, the areal of the first is limited to South America, and the second to Antarctica and adjacent islands (the population of \u003cem\u003eB. gaini\u003c/em\u003e from the Falkland Islands need additional analysis); 2) \u003cem\u003eB. granulosa\u003c/em\u003e and \u003cem\u003eB. gaini\u003c/em\u003e are the same species. In our publication, we will adhere to the more generally accepted first approach (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), but note the need for further study this question.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAs for research on \u003cem\u003eB. gaini\u003c/em\u003e in the area of ​​the Wilhelm Archipelago, in addition to the first finding of this species by Mr. L. Hein in 1909 (Dabay De De\u0026eacute;s 1910), studies are fragmentary. They are represented mainly by references to this species by English and Ukrainian researchers, unpublished scientific reports and several publications (Polishuk et al. \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Chernov et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). This species was described as \u003cem\u003eB. granulosa\u003c/em\u003e, and the findings were mainly presented with information about the discovery of this species within several islands (Galindez, Skua, Mitina, and Uruguay Islands) without coordinates or reference to freshwater bodies. This species was later redefined as \u003cem\u003eB. gaini\u003c/em\u003e (Chernov et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Trokhymets and Dykyy \u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Our article aimed to study the distribution and its mechanisms in freshwater anostracan crustacean \u003cem\u003eB. gaini\u003c/em\u003e in region of ​​the Wilhelm Archipelago.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePlace and date of material collection\u003c/h2\u003e \u003cp\u003eSamples were collected in freshwater bodies in the region of the Wilhelm Archipelago. We used the next classification of freshwater bodies (Trokhymets et al. \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e2024\u003c/span\u003e): 1) \u0026ldquo;Lake\u0026rdquo; not freeze to the bottom, the depth is more than 2 m, and the area is 100 m\u003csup\u003e2\u003c/sup\u003e and more; 2) \u0026ldquo;Pond\u0026rdquo; freezes to the bottom in winter, their depth is less 2 m, and the area is from 10 to 100 m\u003csup\u003e2\u003c/sup\u003e or more with low depth; 3) \u0026ldquo;Rock pool\u0026rdquo; freezes to the bottom in winter, their the depth not exceed 1 m, and the area is less 10 m\u003csup\u003e2\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe samples were collected during the wintering of the 12th Ukrainian Antarctic Expeditions in March 2007, the wintering of the 12th Ukrainian Antarctic Expeditions in January-February 2008, the wintering of the 14th Ukrainian Antarctic Expeditions in January-March 2010, and the season of the 25th Ukrainian Antarctic Expedition in February-April 2020. A total of eight samples were taken in freshwater bodies of four islands and the Cape Rasmussen in 2007, seven samples on six islands in 2008, 18 samples on 12 islands and the Cape Rasmussen in 2010, and 111 samples on 20 islands and three continental capes in 2020. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e presents those freshwater bodies with their geolocation using GPS where \u003cem\u003eB. gaini\u003c/em\u003e was found. Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents those reservoirs where \u003cem\u003eB. gaini\u003c/em\u003e was absent.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRecords of \u003cem\u003eBranchinecta gaini\u003c/em\u003e in the area of the Wilhelm Archipelago\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYear\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIsland\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWater body\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCoordinates\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAbbreviation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eResearcher\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUruguay Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'18\"S 64\u0026deg;13'30\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGalindez Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'55\"S 64\u0026deg;14'43\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V., Dykyy I.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2008\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGalindez Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'55\"S 64\u0026deg;14'43\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2008\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSkua Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;15'18\"S 64\u0026deg;16'28\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2008\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMitina Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'11\"S 64\u0026deg;18'31\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBerthelot Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;19'42\"S 64\u0026deg;08'40\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eDykyy I.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGalindez Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'55\"S 64\u0026deg;14'43\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eDykyy I.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePetermann Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;10'02\"S 64\u0026deg;08'00\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eDykyy I.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUruguay Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLake 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'05.4\"S 64\u0026deg;13'20.5\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eL1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eDykyy I.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWinter Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;15'00\"S 64\u0026deg;15'47\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eDykyy I.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMitina Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'11\"S 64\u0026deg;18'31\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eDykyy I.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIrizar Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'08.7\"S 64\u0026deg;12'01.2\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIrizar Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'08.5\"S 64\u0026deg;12'00.4\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIrizar Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'08.5\"S 64\u0026deg;12'01.6\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIrizar Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'08.4\"S 64\u0026deg;12'01.2\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIrizar Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'08.5\"S 64\u0026deg;12'02.6\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIrizar Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'10.2\"S 64\u0026deg;11'58.2\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIrizar Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'10.5\"S 64\u0026deg;11'55.3\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEight Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'32.7\"S 64\u0026deg;12'35.7\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEight Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'32.6\"S 64\u0026deg;12'35.8\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEight Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'33.8\"S 64\u0026deg;12'34.6\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEight Is. *\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'33.5\"S 64\u0026deg;12'35.9\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUruguay Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'16.4\"S 64\u0026deg;13'18.7\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUruguay Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLake 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'05.4\"S 64\u0026deg;13'20.5\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eL1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrotto Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'19.0\"S 64\u0026deg;15'25.0\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrotto Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'18.7\"S 64\u0026deg;15'24.0\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrotto Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'19.0\"S 64\u0026deg;15'24.3\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMaly Berthelot Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;20'07.7\"S 64\u0026deg;10'29.2\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMaly Berthelot Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;20'13.1\"S 64\u0026deg;10'25.8\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMaly Berthelot Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;20'13.1\"S 64\u0026deg;10'25.0\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMaly Berthelot Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;20'13.0\"S 64\u0026deg;10'28.1\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMaly Berthelot Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;20'12.5\"S 64\u0026deg;10'24.7\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePetermann Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;10'42.3\"S 64\u0026deg;08'42.7\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePetermann Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;09'58.6\"S 64\u0026deg;08'50.2\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBlack Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;15'28.4\"S 64\u0026deg;17'04.6\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMitina Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'11\"S 64\u0026deg;18'31\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGalindez Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'55\"S 64\u0026deg;14'43\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGalindez Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRock pool 19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'54.8\"S 64\u0026deg;14'43.8\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRP19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTrokhymets V.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003eNote. * \u0026ndash; unofficial name (an officially unnamed)\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eFreshwater bodies without \u003cem\u003eBranchinecta gaini\u003c/em\u003e in the area of the Wilhelm Archipelago\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYear\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIsland\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWater body\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCoordinates\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCape Rasmussen*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'51\"S 64\u0026deg;05'05\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePetermann Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP, RP, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;10'25\"S 64\u0026deg;08'06\"W, 65\u0026deg;10'37\"S 64\u0026deg;08'26\"W, 65\u0026deg;10'34\"S 64\u0026deg;08'25\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLocator Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;10'44.4\"S 64\u0026deg;29'31.4\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGalindez Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;15'04\"S 64\u0026deg;14'34\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2008\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCruls I Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;11'48\"S 64\u0026deg;32'19\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2008\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCruls II Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP, P\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;11'25\"S 64\u0026deg;32'15\"W, 65\u0026deg;11'23\"S 64\u0026deg;32'18\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2008\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLocator Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;10'44\"S 64\u0026deg;29'31\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLocator Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP, P\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;10'44\"S 64\u0026deg;29'27\"W, 65\u0026deg;10'44\"S 64\u0026deg;29'31\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNob Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;12'20\"S 64\u0026deg;18'54\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBerthelot Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;19'40\"S 64\u0026deg;08'40\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePetermann Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP, P\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;10'39\"S 64\u0026deg;08'41\"W, 65\u0026deg;10'30\"S 64\u0026deg;08'11\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCruls I Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;11'55\"S 64\u0026deg;32'11\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePl\u0026eacute;neau Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;06'07\"S 64\u0026deg;02'50\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWinter Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'54\"S 64\u0026deg;15'33\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSkua Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;15'03\"S 64\u0026deg;16'14\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRasmussen Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;15'30\"S 64\u0026deg;04'48\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCape Rasmussen*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'50\"S 64\u0026deg;05'05\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLocator Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP, RP, RP, RP, RP, RP, RP, RP, RP, RP, RP, RP, RP, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;10'44\"S 64\u0026deg;29'31\"W, 65\u0026deg;10'43.6\"S 64\u0026deg;29'30.1\"W, 65\u0026deg;10'43.5\"S 64\u0026deg;29'29.7\"W, 65\u0026deg;10'43.4\"S 64\u0026deg;29'33.4\"W, 65\u0026deg;10'43.6\"S 64\u0026deg;29'31.0\"W, 65\u0026deg;10'44.1\"S 64\u0026deg;29'31.2\"W, 65\u0026deg;10'43.8\"S 64\u0026deg;29'31.7\"W, 65\u0026deg;10'43.1\"S 64\u0026deg;29'34.1\"W, 65\u0026deg;10'44.0\"S 64\u0026deg;29'27.0\"W, 65\u0026deg;10'43.6\"S 64\u0026deg;29'33.1\"W, 65\u0026deg;10'43.0\"S 64\u0026deg;29'36.5\"W, 65\u0026deg;10'43.4\"S 64\u0026deg;29'33.4\"W, 65\u0026deg;10'42.9\"S 64\u0026deg;29'36.5\"W, 65\u0026deg;10'43.7\"S 64\u0026deg;29'35.7\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBlakytnookyi Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP, RP, RP, RP, RP, RP, RP, RP, RP, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;12'21.8\"S 64\u0026deg;18'42.0\"W, 65\u0026deg;12'21.7\"S 64\u0026deg;18'42.8\"W, 65\u0026deg;12'20.7\"S 64\u0026deg;18'38.0\"W, 65\u0026deg;12'21.8\"S 64\u0026deg;18'42.7\"W, 65\u0026deg;12'25.7\"S 64\u0026deg;18'51.0\"W, 65\u0026deg;12'20.8\"S 64\u0026deg;18'37.9\"W, 65\u0026deg;12'18.4\"S 64\u0026deg;18'25.7\"W, 65\u0026deg;12'19.1\"S 64\u0026deg;18'20.2\"W, 65\u0026deg;12'18.9\"S 64\u0026deg;18'18.6\"W, 65\u0026deg;12'20.6\"S 64\u0026deg;18'31.8\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIrizar Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP, RP, RP, RP, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'11.8\"S 64\u0026deg;12'01.9\"W, 65\u0026deg;13'12.1\"S 64\u0026deg;12'01.3\"W, 65\u0026deg;13'11.7\"S 64\u0026deg;12'02.6\"W, 65\u0026deg;13'12.8\"S 64\u0026deg;12'00.9\"W, 65\u0026deg;13'13.1\"S 64\u0026deg;12'00.4\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEight Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP, RP, RP, RP, RP, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'32.3\"S 64\u0026deg;12'35.6\"W, 65\u0026deg;13'32.2\"S 64\u0026deg;12'35.5\"W, 65\u0026deg;13'32.6\"S 64\u0026deg;12'35.9\"W, 65\u0026deg;13'33.5\"S 64\u0026deg;12'34.6\"W, 65\u0026deg;13'33.4\"S 64\u0026deg;12'35.4\"W, 65\u0026deg;13'33.9\"S 64\u0026deg;12'34.5\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUruguay Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP, RP, RP, P\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'57.6\"S 64\u0026deg;13'17.6\"W, 65\u0026deg;13'57.3\"S 64\u0026deg;13'21.8\"W, 65\u0026deg;14'08.0\"S 64\u0026deg;13'27.3\"W, 65\u0026deg;14'18.1\"S 64\u0026deg;13'29.8\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrotto Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP, RP, RP, RP, RP, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'19.9\"S 64\u0026deg;15'24.3\"W, 65\u0026deg;14'20.4\"S 64\u0026deg;15'23.6\"W, 65\u0026deg;14'22.2\"S 64\u0026deg;15'19.1\"W, 65\u0026deg;14'23.7\"S 64\u0026deg;15'10.8\"W, 65\u0026deg;14'21.9\"S 64\u0026deg;15'13.7\"W, 65\u0026deg;14'22.8\"S 64\u0026deg;15'14.7\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRasmussen Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP, P, RP, RP, RP, RP, RP, RP, RP, P, P, P, RP, RP, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;15'24.8\"S 64\u0026deg;04'44.7\"W, 65\u0026deg;15'24.7\"S 64\u0026deg;04'43.3\"W, 65\u0026deg;15'24.7\"S 64\u0026deg;04'43.6\"W, 65\u0026deg;15'24.9\"S 64\u0026deg;04'43.2\"W, 65\u0026deg;15'24.9\"S 64\u0026deg;04'43.5\"W, 65\u0026deg;15'25.8\"S 64\u0026deg;04'47.1\"W, 65\u0026deg;15'25.7\"S 64\u0026deg;04'47.2\"W, 65\u0026deg;15'25.8\"S 64\u0026deg;04'47.2\"W, 65\u0026deg;15'25.8\"S 64\u0026deg;04'47.4\"W, 65\u0026deg;15'29.2\"S 64\u0026deg;04'42.1\"W, 65\u0026deg;15'28.6\"S 64\u0026deg;04'43.2\"W, 65\u0026deg;15'28.9\"S 64\u0026deg;04'44.0\"W, 65\u0026deg;15'28.8\"S 64\u0026deg;04'46.2\"W, 65\u0026deg;15'29.2\"S 64\u0026deg;04'45.6\"W, 65\u0026deg;15'29.9\"S 64\u0026deg;04'44.8\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMaly Berthelot Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP, RP, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;20'14.3\"S 64\u0026deg;10'07.8\"W, 65\u0026deg;20'09.0\"S 64\u0026deg;10'18.3\"W, 65\u0026deg;20'09.9\"S 64\u0026deg;10'19.7\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNob Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;12'20.2\"S 64\u0026deg;18'54.2\"W, 65\u0026deg;12'18.4\"S 64\u0026deg;18'54.1\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLeopard Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;15'17.0\"S 64\u0026deg;17'26.4\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGalindez Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP, RP, P, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'53.1\"S 64\u0026deg;14'43.5\"W, 65\u0026deg;14'54.2\"S 64\u0026deg;14'42.7\"W, 65\u0026deg;14'43.1\"S 64\u0026deg;15'22.5\"W, 65\u0026deg;14'57.0\"S 64\u0026deg;14'47.0\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCape Tuxen\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePR, RP, P\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;16'04.0\"S 64\u0026deg;06'58.8\"W, 65\u0026deg;16'04.6\"S 64\u0026deg;06'57.6\"W, 65\u0026deg;16'02.2\"S 64\u0026deg;07'03.3\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHovgaard Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePR, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;07'09.6\"S 64\u0026deg;04'24.3\"W, 65\u0026deg;07'01.8\"S 64\u0026deg;04'20.6\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePl\u0026eacute;neau Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;06'07.1\"S 64\u0026deg;03'22.1\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCape Rasmussen*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'49.7\"S 64\u0026deg;05'05.6\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCape Moot *\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;12'13.3\"S 64\u0026deg;04'30.0\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMoot Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;12'25\"S 64\u0026deg;04'31\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWinter Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'53.2\"S 64\u0026deg;15'51.3\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSkua Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePR, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;15'03.3\"S 64\u0026deg;16'14.1\"W, 65\u0026deg;14'59.0\"S 64\u0026deg;16'11.7\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGreat Yalour Is.*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePR, RP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'06.0\"S 64\u0026deg;09'28.0\"W, 65\u0026deg;14'07.0\"S 64\u0026deg;09'22.7\"W\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eNotes. L \u0026ndash; lake, P \u0026ndash; pond, RP \u0026ndash; rock pool; * \u0026ndash; unofficial name (an officially unnamed)\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSample collection\u003c/h3\u003e\n\u003cp\u003eSamples were collected using a 2-liter sampler. Samples ranging in size from 5 to 20 L were filtered through a 100 \u0026micro;m mesh conical plankton mesh (Janiec \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e1991\u003c/span\u003e; Burian and Trokhymets \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). We additionally used direct collection of fairy shrimp with a hand net (Jo et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) if these crustaceans were visually visible in the reservoir but were not sampled due to low abundance. This method makes it possible to conduct a quantitative assessment of copepods, but only a qualitative assessment (presence or absence) for fairy shrimp, since the latter have a more complex behavior and are not evenly distributed (Pociecha and Dumont \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Animals were fixed in 99% ethanol for further molecular genetic studies (Pokorn\u0026yacute; et al. \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), and some individuals in 4% formaldehyde for morphological analysis (Pociecha and Dumont \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). We also recorded salinity using salinity meter and water temperature by means a mercury thermometer.\u003c/p\u003e\n\u003ch3\u003eTaxonomic identification\u003c/h3\u003e\n\u003cp\u003eThe investigation of \u003cem\u003eB. gaini\u003c/em\u003e in samples from 2007, 2008, and 2010 was carried out in the laboratory of the Educational and Scientific Center \"Institute of Biology and Medicine\" of Taras Shevchenko National University of Kyiv. The study of \u003cem\u003eB. gaini\u003c/em\u003e in 2020 was performed directly in the laboratory of the Ukrainian Antarctic Akademik Vernadsky station. Morphology analysis was done by means a stereomicroscope MBS-12. Adults \u003cem\u003eB. gaini\u003c/em\u003e was taxonomically identified using minor structural features of the structure of the second antenna, gonopodia and genital segments of males (Dabay De De\u0026eacute;s 1910; Jurasz et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1983\u003c/span\u003e; Rogers et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2020a\u003c/span\u003e). Larvae were identified from illustrations in the article about the life cycle of this crustacean (Jurasz et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1983\u003c/span\u003e). Different stages of \u003cem\u003eB. gaini\u003c/em\u003e development can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eMap constructions and photos\u003c/h3\u003e\n\u003cp\u003eMaps were generated with QGIS 3.16 using SCAR Antarctic Digital Database v7.7 2023 by Gerrish et al. (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) and UK Polar Data Centre VERSION 7.3 (Version 1.0) by Gerrish (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Coordinate Reference Systems WGS 84 Antarctic Polar Stereographic EPSG:3031 (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) and WGS 84 UTM zone 20N EPSG:32620 (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e15\u003c/span\u003e) were used for map generation. All photos were taken and provided for publication by the first and second authors.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eAccording to the results of Shapiro-Wilk normality test, data have not normality distribution. Therefore, the nonparametric Mann-Whitney-Wilcoxon test (Bauer \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1972\u003c/span\u003e) was used to determine the effect of depth, salinity, and temperature on the presence or absence of \u003cem\u003eB. gaini\u003c/em\u003e in freshwater bodies. Pearson's chi-squared test (Pearson \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e1900\u003c/span\u003e) was used to analyze the influence of presence of cyanobacterial mat, presence of \u003cem\u003eBoeckella poppei\u003c/em\u003e (Mr\u0026aacute;zek, 1901) (Copepoda, Calanoida), and time sampling (month, year) on the presence or absence of \u003cem\u003eB. gaini\u003c/em\u003e in reservoirs. The study used only reservoirs within islands where \u003cem\u003eB. gaini\u003c/em\u003e had been previously confirmed (in previous studies or during our study). Although freshwater bodies on other islands may be optimal for the species, there is currently no evidence that the species has been introduced there by vectors. Therefore, including these water bodies in the statistical analysis would bias the results. RStudio (v. 1.4.1106, R 4.0.5) is used for all statistical data processing.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003e \u003cem\u003eBranchinecta gaini\u003c/em\u003e was registries in two freshwater bodies of Uruguay and Galindez Islands out of the four examined islands and the Cape Rasmussen in 2007, three reservoirs of three islands from six examined islands in 2008, six freshwater bodies of six islands from 12 examined islands and the Cape Rasmussen in 2010, and 27 reservoirs of nine islands from 20 examined islands and three continental capes in 2020 (see Tables\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Some samples were taken from the same freshwater body (for example, on Galindez Island) in different years of research, so the number of islands with finds of this crustacean is not a simple sum of the studied islands for different years. \u003cem\u003eBranchinecta gaini\u003c/em\u003e was found in the 32 freshwater bodies of 12 islands in the Wilhelm Archipelago (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). This anostracan was registries for the first time in reservoirs of 11 islands. Next, we will consider in more detail the reservoirs and islands where representatives of \u003cem\u003eB. gaini\u003c/em\u003e were registered.\u003c/p\u003e \u003cp\u003e \u003cb\u003e1. Uruguay Island\u003c/b\u003e is one from the Argentine Islands group of Wilhelm Archipelago (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003ea). It is located in the Bellingshausen Sea at a distance of 2 km to the northeast of Galindez Island and about 6 km from the coast of Kyiv Peninsula. The island consists of the northern and southern parts, connected by a narrow isthmus.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eP1 is located on the southern part of the island, on the left side of the central rocky ridge, if going from the south to the north (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003eb). It is located at an altitude of 15 m above sea level, has dimensions in the maximum section of about 50x20 m and a depth of up to 1.5 m. The bottom is rocky, and the walls are covered in places with a brown layer of cyanobacterial mat. Water comes from melting snow and ice. There is no vegetation near the pond. One adult specimen of \u003cem\u003eB. gaini\u003c/em\u003e was detected in P1 in March 2007. Another sample was taken from this pond in April 2020. There were no crustaceans, but this can be explained by the fact that the reservoir was already covered with a five-centimeter layer of ice. A hole had to be drilled in the ice in order to take a sample. We can assume that the adults of \u003cem\u003eB. gaini\u003c/em\u003e could have laid wintering eggs and died.\u003c/p\u003e \u003cp\u003eP9 is located on the southern part of the island, on the right side of the central rocky ridge (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003ec). It is located at an altitude of 11 m above the sea level, has dimensions in the maximum section of about 120x50 m (the size of the this freshwater pond was accurately determined later and turned out to be larger than it was measured at the time of sampling, when the reservoir was partially frozen and covered with snow) and a depth of up to 0.7 m. The bottom is rocky, and the walls are covered in places with a brown layer of cyanobacterial mat. Water comes from melting snow and ice. There is no vegetation near the pond. Several adult individuals of \u003cem\u003eB. gaini\u003c/em\u003e were registries under a thin layer of ice in P9 in April 2020.\u003c/p\u003e \u003cp\u003eElongated L1 is located in the center of the island\u0026rsquo;s northern part in a depression between rocky ridges (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003ed\u0026ndash;e). It is located at an elevation of 40 m and has dimensions of about 300x80 m (it were determined later similarly to P10) and a maximum depth of 8 m in the northern part of the lake. It is the largest lake in the area of Argentine Islands. The bottom is stone, in places covered with organic matter of green color; the walls are covered with a thin cyanobacterial mat. Water comes from melting glaciers and snow. Nearby are small fields of moss and lichens. L1 is one of the few reservoirs in the region of our studies that does not freeze to bottom in winter and where representatives of the fauna can actively function in the coldest season. The lake is connected by canals to a subglacial lake. The latter is located under a glacial dome about 12 m thick and has a depth of 9 m. The connection of these two lakes confirms the fact that a hole was made in the ice dome by thermal drilling and parts of the limbs of \u003cem\u003eB. gaini\u003c/em\u003e were found in the sample taken (Chernov et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The existence of this crustacean in a closed subglacial ecosystem is hardly possible, since this species is not a troglobiont. Thus, L1 is a unique ecosystem in which classic groups of Antarctic freshwater hydrobionts and representatives of troglobionts can potentially be found. It was previously proposed to use L1 as the Base station №2 for continuous monitoring of \u003cem\u003eB. poppei\u003c/em\u003e (Trokhymets 2024). However, this freshwater reservoir is also optimal for long-term monitoring of \u003cem\u003eB gaini\u003c/em\u003e and other aquatic biota, as research can be conducted even in winter under favorable weather conditions (when the island is accessible by open water or ice). Therefore, we propose to consider this reservoir as the \u0026ldquo;Basic freshwater hydrobiological station №1\u0026rdquo; for permanent monitoring of hydrobionts and the Base station №2 for long-term monitoring of \u003cem\u003eB. gaini\u003c/em\u003e and \u003cem\u003eB. poppei\u003c/em\u003e in this region of the Wilhelm Archipelago (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). \u003cem\u003eBranchinecta gaini\u003c/em\u003e was registered in L1 in February 2010 and March 2020. Nine females, four males and six juveniles (19 in total) were collected in 2010. Three females and 10 juveniles (13 in total) were caught in 2020. Samples were taken for the purpose of monitoring hydrobionts every week from March 10 to April 14, 2020. \u003cem\u003eBranchinecta gaini\u003c/em\u003e was present in the samples every times, although their number decreased. So, three live (one female and two males) and one dead individuals were found in the sample on April 14.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eProposed base stations for hydrobiological research in this region of the Wilhelm Archipelago\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBase station\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIsland\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFB\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCoordinates\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eObject of monitoring\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBFHS №1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUruguay Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLake 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'05.4\"S 64\u0026deg;13'20.5\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAll hydrobionts\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBFHS №2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSkua Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLake\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;15'10\"S 64\u0026deg;15'40\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAll hydrobionts\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBasic station № 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIrizar Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;13'08.7\"S 64\u0026deg;12'01.2\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eBranchinecta gaini\u003c/em\u003e, \u003cem\u003eBoeckella poppei\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBasic station № 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUruguay Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLake 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'05.4\"S 64\u0026deg;13'20.5\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eB. gaini\u003c/em\u003e, \u003cem\u003eB. poppei\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBasic station № 3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGalindez Is.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePond 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'55\"S 64\u0026deg;14'43\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eB. gaini\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65\u0026deg;14'56.7\"S 64\u0026deg;14'47.0\"W\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eB. poppei\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eNotes. FB \u0026ndash; freshwater body; BFHS \u0026ndash; \u0026ldquo;Basic freshwater hydrobiological station\u0026rdquo;; Pond 7 from Irizar Island, as well as the freshwater bodies of Eight and Grotto Islands can be an alternative for long-term monitoring \u003cem\u003eB. gaini\u003c/em\u003e and \u003cem\u003eB. poppei\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003e2. Galindez Island\u003c/b\u003e is one from the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e5\u003c/span\u003ea). It is located in the Bellingshausen Sea at a distance 7 km from the continental coast of Kyiv Peninsula.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eP2 is located near the highest point of the island (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e5\u003c/span\u003eb-c). This reservoir is very similar to the rock pool, but we will consider it as a pond according to the classification used. The pond has a more or less rounded shape and dimensions of approximately 4x4 m. Depth up to 30 cm. The reservoir is formed as a result of melting snow. Nearby, there are only bare rocks with small patches of moss and lichen. A brown cyanobacterial mat 1 mm thick is visible on the walls. \u003cem\u003eBranchinecta gaini\u003c/em\u003e was found in P2 in March 2007 (12 adult specimens), in February 2008 (10), in January 2010 (9), and in February 2020 (15). Thus, this is the only freshwater body in which these crustaceans were registered during all four years of research. We are offered this reservoir as the Base station №3 for the long-term monitoring of \u003cem\u003eB. gaini\u003c/em\u003e population dynamics. In addition, it is proposed to move the Base station № 3 for monitoring of \u003cem\u003eB. poppei\u003c/em\u003e from the Grotto Island (Trokhymets et al. \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) to Galindez Island (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), where a new population of this copepod was recently discovered (Nabokin et al. \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eRP19 are located on the top of a flat hill. The reservoir is dimensions of 3x3 m and a depth of up to 0.3 m. The bottom is rocky and covered with organic matter. The walls are covered with a brown a layer of cyanobacterial mat. Water comes from melting snow. Water was opaque at the time of sampling, which is due to the bloom of phytoplankton. Nearby there are patches of moss and lichens. \u003cem\u003eBranchinecta gaini\u003c/em\u003e was found in March 2020. 23 sexually mature representatives were registries in the sample.\u003c/p\u003e \u003cp\u003e \u003cb\u003e3. Skua Island\u003c/b\u003e is one from the Argentine Islands (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e6\u003c/span\u003ea). It is located in the Bellingshausen Sea at a distance of 0.7 km to the southwestern from the Ukrainian Antarctic Akademik Vernadsky station on neighboring Galindez Island and about 6 km from the coast of Kyiv Peninsula.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eRP1 is located on the terrace of the slope on the southwest coast of Skua Island. The shape of this freshwater body is elongated polygonal. Its dimensions reach 2x1 m and the depth is 0.3 m. The reservoir was formed as a result of melting snow. Nearby are small patches of moss and lichen. The stone bottom is covered in places with a layer of green-brown organic matter (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e6\u003c/span\u003eb). A brown cyanobacterial mat (1 mm thick) overgrown on the walls. Seven sexually mature specimens of \u003cem\u003eB. gaini\u003c/em\u003e were selected within this reservoir in February 2008.\u003c/p\u003e \u003cp\u003eIn addition, one of the largest freshwater bodies in this region of the Wilhelm Archipelago deserves special attention (Fig.\u0026nbsp;6с). This reservoir is located in the northern part of the island, not far from the ice dome and a number of stone hills (65\u0026deg;15'10\"S 64\u0026deg;15'40\"W). It was formed as a result of the melting of the glacier of the island and snow. Much of it is covered with ice, so it is difficult to determine the exact dimensions. This reservoir suffered a maximum thawing in February-March 2020, resulting in was possible to determine its approximate dimensions: the maximum size was 200x85 m. The reservoir has maximum depths more than 2 m. In this regard, we consider this freshwater body as a lake. Crustaceans were not detected by visual monitoring, but a more detailed analysis of hydrobionts is required. Unfortunately, it was not possible to fundamentally investigate of hydrobionts in this freshwater body in 2020. In the future, it will be possible to trace the processes of settlement of new biota within the reservoir. In addition, it is convenient for research, as it is located near Galindez Island. We propose to consider this reservoir as the \u0026ldquo;Basic freshwater hydrobiological station №2\u0026rdquo; for constant monitoring of hydrobionts (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cb\u003e4. Mitina Island\u003c/b\u003e (unofficial name, an officially unnamed) is one from the small islands group The Barchans from the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e7\u003c/span\u003ea). The island located most northeast of other The Barchans and in the Bellingshausen Sea at a distance of 2 km to the west from the Galindez Island and about 8.5 km from the continental coast of Kyiv Peninsula.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eP3 is located on a stone plateau of the northwestern coast of the island at an altitude of 12 m (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e7\u003c/span\u003eb). The shape of this freshwater body has the appearance of an irregular quadrangular with unequal sides. The size is 4x3 m, and its depth is up to 0.3 m. P3 was formed as a result of melting snow. There are small patches of moss and lichen nearby. The bottom is stony, in the deepest part of semi-decomposed moss have accumulated. A thin layer of brown cyanobacterial mat covers the walls and bottom of the reservoir. \u003cem\u003eBranchinecta gaini\u003c/em\u003e were collected in this reservoir in February 2008 (14 sexually mature specimens), in February 2010 (7), and in February 2020 (24).\u003c/p\u003e \u003cp\u003e \u003cb\u003e5. Berthelot Island\u003c/b\u003e is one from the Berthelot Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e8\u003c/span\u003ea). It is located in the Bellingshausen Sea at a distance of 10 km to the southeast of Galindez Island and about 3.5 km from the continental coast of Kyiv Peninsula.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eP4 is located in the northern part of the island, at the base of the thin peninsula, which is directed to the northeast. The reservoir was formed on a stone terrace near the hill. Stone blocks are scattered along its coast, which form a depression of a polygonal shape (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e8\u003c/span\u003eb-c). Its total area reaches approximately 12 m\u003csup\u003e2\u003c/sup\u003e, and the depth is 0.4 m. P4 is flowing, and its level is maintained thanks to melted snow. All around are large fields of moss and patches of lichen. At the bottom is an accumulated layer of semi-decomposed moss, and the walls are covered with a layer of cyanobacterial mat. Three sexually mature specimens of \u003cem\u003eB. gaini\u003c/em\u003e were registries in the reservoir in January 2010.\u003c/p\u003e \u003cp\u003e \u003cb\u003e6. Petermann Island\u003c/b\u003e is located in the Bellingshausen Sea at a distance of 9 km northeast of Galindez Island and about 2 km from the continental coast of Kyiv Peninsula (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003ea).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eP5 is located on the northeastern part of the island at an altitude of 7 m above sea level (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003eb). The reservoir is formed in a stone gorge and has an L-shape. Its dimensions reach 7x2 m, and the depth is 0.4 m. The rocky walls are covered with a thick layer of brownish-red cyanobacterial mat (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003ec), and there is a small amount of silt from decomposed moss at the bottom. Water comes from melting snow. There are small patches of carpet moss up to tens of centimeters in size and lichens nearby. 20 sexually mature specimens of \u003cem\u003eB. gaini\u003c/em\u003e were collected in March 2010.\u003c/p\u003e \u003cp\u003eRP18 is located in the coastal area of ​​the southern part of the island at a height of 8 m above sea level (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003ed). The reservoir has an irregular shape that vaguely resembles a cross. Its maximum dimensions reach 3x2 m, and the depth is 0.3 m. It is located in a hollow, on a slope between large stone blocks. The walls have a thin layer of brown cyanobacterial mat; the bottom is covered with a several-centimeter layer of silt and half-decomposed moss. Meter-long patches of moss, among which there are small (up to 20 cm) patches of \u003cem\u003ePrasiola\u003c/em\u003e algae, are located on the bank of the freshwater body. 15 adults of \u003cem\u003eB. gaini\u003c/em\u003e were collected in February 2020. In general, this reservoir is the only one in our studies with the presence of anostracans, which was significantly influenced by the local avifauna. The fact is that a few tens of meters above and below this reservoir there are small colonies of the Gentoo Penguin (\u003cem\u003ePygoscelis papua\u003c/em\u003e (Forster, 1781)). Accordingly, a small amount of feathers and guano of birds entered the reservoir together with the melt water. As a result, the water is opaque due to the presence of organic matter, and feathers float on the surface. RP18 is not as polluted as the reservoirs in the middle of the penguin colony and where crustaceans have never been found.\u003c/p\u003e \u003cp\u003eP11 is located in the northern part of the island at an altitude of 16 m above sea level (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003ee). The rhomboid reservoir is formed in a stone hollow. It has dimensions of 5x3 m and a depth of up to 0.4 m. The walls are covered with a thin layer of brown cyanobacterial mat to a depth of up 30 cm. There is some silt at the bottom from decomposed moss. Water comes from melting snow and ice. Patches of moss ranging in size from centimeters to meters and lichens are nearby. A large number of anostracans were found feeding by cyanobacterial mat on stones during the visual observation in February 2020. 62 individuals of \u003cem\u003eB. gaini\u003c/em\u003e were registered in the sample (56 adults, one juvenile, and five larvae).\u003c/p\u003e \u003cp\u003e \u003cb\u003e7. Winter Island\u003c/b\u003e is one from the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e10\u003c/span\u003ea). It is located in the Bellingshausen Sea at a distance of 0.15 km from the Ukrainian Antarctic Akademik Vernadsky station on neigh boring Galindez Island and about 6.5 km from the continental coast of Kyiv Peninsula.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eRP2 has an oval shape and is located near the coast (Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e10\u003c/span\u003eb), opposite Skua Island. It is formed in a hollow between stone blocks. The size of the reservoir is 3x2 m, and the depth reaches 0.4 m. The walls are covered with a thin layer of brown cyanobacterial mat, and on the gravel bottom is a layer of decomposed and semi-decomposed moss up to 5 cm thick. Water comes from melting snow and ice. Around this freshwater body are fields of moss and lichens. Three adults of \u003cem\u003eB. gaini\u003c/em\u003e were selected in February 2010.\u003c/p\u003e \u003cp\u003e \u003cb\u003e8. Irizar Island\u003c/b\u003e is one from the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e11\u003c/span\u003ea). It is located in the Bellingshausen Sea at a distance of 3.5 km to the northeast of Galindez Island and about 6 km from the continental coast of Kyiv Peninsula.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe elongated polygonal P6 is located on the terrace of the slope of the northernmost rocky ridge of the island at an altitude of 15 m above sea level (Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e11\u003c/span\u003eb). Its dimensions reach 6x2 m, and the depth is 0.5 m. The stone walls are covered with a thin layer of brown cyanobacterial mat, and at the bottom is a layer of decomposed and semi-decomposed moss silt (up to 0.1 m). Water enters the reservoir from melting snow. There are small moss fields and lichens around. Seven sexually mature individuals of \u003cem\u003eB. gaini\u003c/em\u003e were found in February 2020. P6 was chosen as the Base station №1 for long-term monitoring of the phenology of \u003cem\u003eB. gaini\u003c/em\u003e and \u003cem\u003eB. poppei\u003c/em\u003e (Trokhymets et al. \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eRP3 is located close to the shore, slightly to the east of P6. The reservoir is located in the depression of the terrace at a height of 12 m above sea level and has a triangular shape. Its dimensions reach 1.5 x 0.5 m, and the depth is up to 0.3 m. The stone walls and bottom are covered with a thin layer of cyanobacterial mat. Water in the reservoir comes from melting snow. Two \u003cem\u003eB. gaini\u003c/em\u003e adults were found in the samples from RP3 in February 2020.\u003c/p\u003e \u003cp\u003eRP4 and RP5 are located to the north of P6 (Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e11\u003c/span\u003ec). The spindle-shaped PR4 is formed on a rock terrace at a height of 14 meters above sea level. It has dimensions of 2x1 m and a depth of up to 0.3 m. The quadrangular PR5 is located on the rock terrace at a height of 15 m, a few meters and slightly higher than RP4. It has dimensions of 2x1.5 m and a depth of up to 0.4 m. The walls of both reservoirs are covered with a thin layer of brown cyanobacterial mat, and the bottom is covered with a thin layer of organic matter from decomposed moss. They receive water as a result of melting snow. A small amount of moss (tens of centimeters) and lichens are placed near them. Accordingly, five and six sexually mature individuals of \u003cem\u003eB. gaini\u003c/em\u003e were found in both freshwater bodies in February 2020.\u003c/p\u003e \u003cp\u003eP7 formed on the terrace of the rock slope at a height of 12 m above sea level, somewhat to the north-west of the other reservoirs. It has the shape of an irregular quadrangle, the dimensions are 10x3 m and the depth is 1 m. The stone walls are covered with a thin layer of brown cyanobacterial mat; the bottom is free of silt. One sexually mature individual of \u003cem\u003eB. gaini\u003c/em\u003e was caught in March 2020.\u003c/p\u003e \u003cp\u003eP8 is located on a terrace on one of the hills of the island at an altitude of 21 m above sea level (Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e11\u003c/span\u003ed). The round reservoir has dimensions of 20x20 m and a depth of up to 1 m. The walls are covered with a thin layer of brown cyanobacterial mat up to 30 cm deep, and the bottom of small stones contains a thin layer of silt from decomposed moss. Water will fill the reservoir as a result of melting snow. Moss and lichens grow around. Seven \u003cem\u003eB. gaini\u003c/em\u003e juveniles and larvae were detected in the sample in February 2020. It is worth noting that this is the only freshwater body of the island, where larval stages and juveniles of these crustaceans were found. There were no sexually mature individuals.\u003c/p\u003e \u003cp\u003eRP6 is located in a depression on a rock slope at an altitude of 8 m above sea level. Its dimensions are 2x1.5 m, and the depth is 0.3 m. There is a thin layer of brown cyanobacterial mat on the walls. The bottom is stony, in places covered with a layer of decomposed moss. Water enters the reservoir as a result of melting snow. There are small patches of moss and lichen around. It is worth noting that at the time of sampling, the reservoir was already covered with a three-centimeter layer of ice. Three \u003cem\u003eB. gaini\u003c/em\u003e adults were detected in the sample in March 2020.\u003c/p\u003e \u003cp\u003e \u003cb\u003e9. Eight Island\u003c/b\u003e (unofficial name, an officially unnamed) is one from the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e12\u003c/span\u003ea). It is located in the Bellingshausen Sea at a distance of 3 km to the northeast of Galindez Island and about 6 km from the continental coast of Kyiv Peninsula.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe island consists of northern and southern parts connected by an isthmus. Samples were taken within the southern part of the island. RP7 is located on the terrace of the northern slope of this part of the island at an altitude of 8 m above sea level (Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e12\u003c/span\u003eb). It has the shape of a triangle, the base of which is placed under the ice, and the sharp corner is directed down the slope. Its dimensions are 3x2 m, and the depth is up to 0.3 m. The stone walls are covered with a thin layer of cyanobacterial mat, and at the bottom there is silt from semi-decomposed moss. Water constantly flows into this reservoir due to the melting of ice and snow. Excess water flows below and forms a cascade of small rock pools, where crustaceans have also been found. However, this is a single system and therefore these rock pools were not considered as separate bodies of water. Nearby there are small areas with mosses and lichens. Five sexually mature individuals of \u003cem\u003eB. gaini\u003c/em\u003e were found in the sample in February 2020.\u003c/p\u003e \u003cp\u003eSeveral separate rock pools were also found in this area, three of which were found to contain crustaceans. RP 8\u0026ndash;10 have a rounded or polygonal shape, dimensions 2\u0026ndash;1x1\u0026ndash;0.5 m and a depth of 0.2\u0026ndash;0.3 m (Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e12\u003c/span\u003ec). The walls and bottom of these reservoirs are covered with a cyanobacterial mat. Water comes from melting snow and ice. Several sexually mature individuals of \u003cem\u003eB. gaini\u003c/em\u003e were registered in samples in February 2020 (RP8\u0026ndash;3 specimens, RP9\u0026ndash;2, RP10\u0026ndash;2).\u003c/p\u003e \u003cp\u003e \u003cb\u003e10. Grotto Island\u003c/b\u003e is one from the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e13\u003c/span\u003ea). It is located in the Bellingshausen Sea at a distance of 0.4 km to the north of Galindez Island and about 7 km from the continental coast of Kyiv Peninsula.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe elongated RP11 is located on the northwest coast of the island 20 m from the shore and at an altitude of 5 m above sea level. Its maximum dimensions reach 10x1 m, and the depth is 0.4 m. The reservoir is located in a gap between large stone blocks (Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e13\u003c/span\u003eb). The stone walls and bottom are covered with a layer of brown cyanobacterial mat 2 mm thick, and at the bottom in places there is silt of decomposed moss. 70 sexually mature individuals of \u003cem\u003eB. gaini\u003c/em\u003e were found in the sample from the deepest part of RP11 in March 2020.\u003c/p\u003e \u003cp\u003eNearby are two more small freshwater bodies RP12 (Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e13\u003c/span\u003ec) and RP13. The dimensions of RP12 are 4x2 m, RP13 are 2x1 m. The shape of these reservoirs has the appearance of irregular polygons. Their depth reaches 0.2\u0026ndash;0.3 m. The walls of the reservoirs are covered with a thin layer of cyanobacterial mat, although in some places its thickness reached 2 mm. Water comes as a result of melting snow. Accordingly, 11 and five sexually mature individuals of \u003cem\u003eB. gaini\u003c/em\u003e were caught in reservoirs in March 2020. There are other shallow rock pools in the area with lots of semi-degraded and decomposed moss where no anostracans were found.\u003c/p\u003e \u003cp\u003e \u003cb\u003e11. Maly Berthelot Island\u003c/b\u003e (unofficial name, an officially unnamed) is one from the Berthelot Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e8\u003c/span\u003ea). It is located in the Bellingshausen Sea at a distance of 11 km to the southeast of Galindez Island and about 5 km from the continental coast of Kyiv Peninsula.\u003c/p\u003e \u003cp\u003eThe elongated P10 is located on the elevation of the northern part of the island at an altitude of 39 m above sea level (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e8\u003c/span\u003ed). Its dimensions are 20x5 m, and the depth is 0.5 m. The bottom is stony, in places covered with a layer of decomposed and semi-decomposed moss. On the walls in places there is a brown cyanobacterial mat up to 2 mm thick. Mossy fields and lichens are located around the reservoir. The water is transparent; it replenishes the reservoir as a result of melting snow. 83 adults of \u003cem\u003eB. gaini\u003c/em\u003e were selected in March 2020.\u003c/p\u003e \u003cp\u003eRP14 is located on the highlands of the central part of the island at an altitude of 41 m above sea level. The shape of the reservoir somewhat resembles the letter W. Its dimensions are 5x2 m, depth 0.2 m. The bottom is stony, covered with a layer of decomposed and semi-decomposed moss. Along the edges of the freshwater body, moss occupies the entire space from the bottom to the surface of the water, and only in its central part is there free water, where anostracans are concentrated. The walls are covered with a thick brown layer of cyanobacterial mat. Smaller rock pools of various shapes (RP15\u0026ndash;17) are located around. Their size does not exceed several m\u003csup\u003e2\u003c/sup\u003e, and the depth is up to 0.2 m. On their stone bottom there is semi-decomposed moss, and the walls are covered with a layer of cyanobacterial mat. Sexually mature individuals of \u003cem\u003eB. gaini\u003c/em\u003e were found in all four rock pools in March 2020: RP14\u0026ndash;5 specimens, RP15\u0026ndash;3, RP16\u0026ndash;7, and RP17\u0026ndash;11.\u003c/p\u003e \u003cp\u003e \u003cb\u003e12. Black Island\u003c/b\u003e is one from the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig15\" class=\"InternalRef\"\u003e14\u003c/span\u003ea). It is located in the Bellingshausen Sea at a distance of 1.5 km southwest of Galindez Island and about 7 km from the mainland coast of the Kyiv Peninsula.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eP12 is located on the western part of the lake, 15 m from the shore at a height of 5 m above sea level. The reservoir has dimensions of 10x4 m and a depth of up to 0.4 m. Stone walls and the bottom up to a depth of 30 cm are covered with a layer of brown cyanobacterial mat up to 2\u0026ndash;3 mm thick. At the bottom there is a large amount of silt from decomposed moss (Fig.\u0026nbsp;\u003cspan refid=\"Fig15\" class=\"InternalRef\"\u003e14\u003c/span\u003eb), and near the shore is semi-decomposed and fresh moss. Water comes from melting snow. Meter-sized moss fields are located close to the reservoir. There are lichens. 37 \u003cem\u003eB. gaini\u003c/em\u003e individuals were found in the sample (28 sexually mature individuals and 9 juveniles) in February 2020.\u003c/p\u003e \u003cp\u003eAn assessment of the influence of certain factors on the presence of \u003cem\u003eB. gaini\u003c/em\u003e in water bodies gave the following results. Mann\u0026ndash;Whitney\u0026ndash;Wilcoxon test results indicate the depth of sampling affected the possibility of encountering \u003cem\u003eB. gaini\u003c/em\u003e \u0026ndash; on average, samples were found more often at greater depths (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Despite this, this species was recorded at all depths within the study \u0026ndash; from 0.1 m to 1 m. However, \u003cem\u003eB. gaini\u003c/em\u003e were found in water bodies 0.1 m deep only once. Water temperature and salinity did not affect the probability of encountering individuals of this species. In general, these two indicators varied within relatively narrow ranges.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of mean of the water body depth, water temperature, and salinity, and their impact on \u003cem\u003eBranchinecta gaini\u003c/em\u003e presence in the water body\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePresence of \u003cem\u003eB.\u0026nbsp;gaini\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMedian\u003c/p\u003e \u003cp\u003e(Q25% \u0026ndash; Q75%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNumber of samples\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eW**\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eDegrees of freedom\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003eDepth, m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.30 (0.30\u0026ndash;0.40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e928.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.0004\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e69\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.20 (0.20\u0026ndash;0.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003et, \u0026deg;C\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.04\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.20 (1.55\u0026ndash;2.60)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e418.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.5127\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.19\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.20 (2.10\u0026ndash;2.60)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003eSalinity, \u0026permil;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.0817\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0191\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.0570 (0.0425\u0026ndash;0.0640)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e487.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.0661\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e52\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.0787\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0198\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.0490 (0.0400\u0026ndash;0.0550)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003eNote. W** \u0026ndash; Mann\u0026ndash;Whitney\u0026ndash;Wilcoxon test statistic value\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eChi-squared analysis demonstrates the absence of dependence of the presence of \u003cem\u003eB. gaini\u003c/em\u003e in the catch on the presence of \u003cem\u003eB. poppei\u003c/em\u003e in the reservoir (_X_1\u0026thinsp;=\u0026thinsp;2.797, _p_ = 0.0944), month (_X_3\u0026thinsp;=\u0026thinsp;0.853, _p_ = 0.3557) or year (_X_3\u0026thinsp;=\u0026thinsp;3.416, _p_ = 0.0646) of material collection. The presence of cyanobacterial mats statistically affected the presence of this species in a water body (_X_1\u0026thinsp;=\u0026thinsp;4.255, _p_ = 0.0391). However, few reservoirs were without mats for the test results to be considered truly significant too. Only six times were samples taken in reservoirs where mats were not recorded, but \u003cem\u003eB. gaini\u003c/em\u003e was not found in any of them.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe distribution of \u003cem\u003eB. gaini\u003c/em\u003e in the area of ​​the Wilhelm Archipelago was studied in freshwater reservoirs of the islands and capes of the Antarctic coast. The territory of our research stretched from north to south for 25 km from Hovgaard Island to the Berthelot Islands group and 22 km from west to east from the Cruls Islands group to the continental coast. This made it possible to obtain new data on the freshwater fauna of this Antarctic region.\u003c/p\u003e \u003cp\u003eLong-term studies have shown that the number of reservoirs and islands, within which representatives of \u003cem\u003eB. gaini\u003c/em\u003e were found, increased over time: years \u0026ndash; 2007 \u0026rarr; 2008 \u0026rarr; 2010 \u0026rarr; 2020, the number of reservoirs \u0026ndash; 2 \u0026rarr; 3 \u0026rarr; 6 \u0026rarr; 27, the number of islands \u0026ndash; 2 \u0026rarr; 3 \u0026rarr; 6 \u0026rarr; 9. Some islands and reservoirs are repeated in studies for different years, but the general trend remains the same. This dependence is related to the total number of investigated water bodies and islands/capes. The fact is that this number of them also mostly increased over time: the number of studied reservoirs \u0026ndash; 8 \u0026rarr; 7 \u0026rarr; 18 \u0026rarr; 111, the number of studied islands/capes \u0026ndash; 5 \u0026rarr; 6 \u0026rarr; 13 \u0026rarr; 23. An important aspect of obtaining new data on the distribution of \u003cem\u003eB. gaini\u003c/em\u003e also became the hydrobiologists from the Ukrainian Antarctic Akademik Vernadsky station on Galindez Island, since it the work of the first author was the beginning of the modern study of this crustacean in this region in 2007\u0026ndash;2008. The active study of the freshwater fauna of the region actually began from that moment, growing over time. In addition, this species was first described from the freshwater reservoirs of Petermann Island and small adjacent islands of the Wilhelm Archipelago back in 1910 (Dabay De De\u0026eacute;s 1910). Therefore, it is unlikely that such an active resettlement could have occurred during the 14-year period of research (from 2007 to 2020), given that almost 100 years passed from the first finding of this species within the Wilhelm Archipelago to the beginning of our research. The species, which was in this region even 100 years ago, had enough time to populate a significant part of the freshwater bodies of this region (Polishuk et al. \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Chernov et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). On the other hand, this species was not registered by us within the 15 studied islands and capes. These areas contain reservoirs with the necessary living conditions for these crustaceans. Moreover, a number of water bodies without \u003cem\u003eB. gaini\u003c/em\u003e were found on the islands where this species was recorded. It can be concluded that this anostracan is a common species for this region, which is gradually spreading to new territories. This confirms the fact that \u003cem\u003eB. gaini\u003c/em\u003e has not disappeared from any reservoirs where it was previously registered during our research (P2, P3, and others), nor has it appeared where it was previously absent (for example, the freshwater reservoirs of Locator Island).\u003c/p\u003e \u003cp\u003eFirst, we will consider the history of the appearance of \u003cem\u003eB. gaini\u003c/em\u003e in the Antarctic in order to better understand the modern mechanisms of the distribution of the southernmost species of anostracans (Rogers et al. \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2020b\u003c/span\u003e). For this, it is necessary to consider the main theories of the appearance of this crustacean in the Antarctic, which are distribution from other regions of the planet and endemism. Most scientists deny the possibility of endemism of this crustacean, since it is unlikely that its eggs could survive the freezing of water bodies for hundreds of years. In addition, the active phase of the life cycle of \u003cem\u003eB. gaini\u003c/em\u003e takes place during the Antarctic summer, when optimal conditions for its development occur, namely liquid water and positive temperatures (Jurasz et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1983\u003c/span\u003e). Such a life cycle is facilitated by the metabolic eurythermy characteristic of this species (Peck \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2004\u003c/span\u003e, Pociecha \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). It is not characteristic of the majority of Antarctic terrestrial invertebrates, which are dominated by slow life cycles with activation during the Antarctic summer. Thus, \u003cem\u003eB. gaini\u003c/em\u003e is not a classic Antarctic species. It did not adapt to Antarctic conditions, but used the classic set of adaptations of anostracans to survive adverse conditions of existence. The latter include resistance to adverse egg conditions and their ability to spread passively, as well as the metabolic flexibility of larvae, juveniles, and sexually matured representatives (Hawes \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Although the feeding behavior of the detritophagous \u003cem\u003eB. gaini\u003c/em\u003e is somewhat different from other filter feeders of the genus \u003cem\u003eBranchinecta\u003c/em\u003e (Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2008\u003c/span\u003e), its life strategy has little to do with adaptation to Antarctic conditions (Peck et al. \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). This refutes the theory of endemism and favors the theory of spread of this anostracan from South America to the freshwater ecosystems of Antarctica.\u003c/p\u003e \u003cp\u003e \u003cem\u003eBranchinecta gaini\u003c/em\u003e eggs were most likely transferred from the freshwater bodies of Chile to the reservoirs of different groups of islands (Falkland Islands, South Georgia, South Orkney Islands, South Shetland Islands), and directly to Antarctica (James Ross Island) using passive dispersal vectors. In general, settlement in the Antarctic took place both from South America and from the corresponding groups of islands. But these were not unidirectional movements of populations, since the most likely transfer of this species could also occur in the opposite direction (Hawes \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Further, gradual resettlement took place from James Ross Island in the direction of Marguerite Bay, where environmental conditions allowed representatives of this species to survive (Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2008\u003c/span\u003e) The formation of multiple populations began with local resettlement events when \u003cem\u003eB. gaini\u003c/em\u003e reached new regions of the Antarctic (Hawes \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe main theory of colonization of \u003cem\u003eB. gaini\u003c/em\u003e of freshwater bodies of Antarctic is the spread of this species at the stage of eggs in the last 10000 years. Accordingly, supporters of this approach believe that this species appeared in the reservoirs of the Antarctic islands after The Penultimate Glacial Maximum. It lasted 20-18000 BP and at that time Antarctica was almost completely covered with ice (Ralph \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e1967\u003c/span\u003e). Previously, the oldest findings were considered to be eggs' microfossils of \u003cem\u003eB. gaini\u003c/em\u003e with the James Rose Island aged about 4200 BP (Bj\u0026ouml;rck et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1996\u003c/span\u003e) and from the Signy Island of South Orkney Islands aged about 5500 BP (Jones et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2000\u003c/span\u003e). Later the eggs' microfossils of this crustacean on the Horseshoe Island in Marguerite Bay aged about 9300 BP was found (Hodgson et al. \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). However, the molecular clock analysis of COI and the analysis of the geographical distribution haplotypes of \u003cem\u003eB. gaini\u003c/em\u003e were recently conducted. The results of these studies indicate that this species has survived the last glacial period in an unknown refuge in Antarctic at the moment (Pokorn\u0026yacute; et al. \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSecondly, the species must survive and gain a foothold when entering new territories. As we have already understood, this is mainly facilitated not by adaptation to extreme conditions of existence in \u003cem\u003eB. gaini\u003c/em\u003e, but characteristic of this group of animals by general organizational features. Let's consider the main ones against the background of environmental factors that can limit the spread of this species:\u003c/p\u003e \u003cp\u003e1) \u003cem\u003eBranchinecta gaini\u003c/em\u003e withstands a wide range of fluctuations of a number of abiotic factors, the key of which for survival in the extreme conditions of the Antarctic is temperature. Representatives of this species have wide amplitude of physiological flexibility, which allows them to withstand temperature fluctuations of up to 50\u0026deg;C. Mature individuals can withstand temperatures up to 25\u0026deg;C during the Antarctic summer, and overwintering eggs tolerate temperatures down to -25\u0026deg;C (Peck \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Adults do not have anti-incision proteins in the hemolymph, the crystallization temperature of which is -5\u0026deg;C (Hawes et al. \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). It is worth noting that as a result of global warming and other changes, the habitat of \u003cem\u003eB. gaini\u003c/em\u003e is also gradually being transformed. The active stages of the development of this species receive more time that improved conditions for the passage of the main processes inherent in living organisms (growth, nutrition, and reproduction).\u003c/p\u003e \u003cp\u003eThe temperature also affects the amount of oxygen, which is necessary for the life processes of \u003cem\u003eB. gaini\u003c/em\u003e. Representatives of this species began to use more oxygen with the increase in water temperature and vice versa (Pociecha \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). This, in turn, makes it possible to extend the time of active stages of development, since adults can exist even under ice. At the same time, the lack of oxygen due to the ice cover of the water surface is compensated for a certain time by the decrease in oxygen needs of mature individuals of anostracans. We observed how for three weeks (March-April 2020) some reservoirs of the Uruguay and Irizar islands were covered with a layer of ice, but live crustaceans were still present there at the time of sampling. This important aspect allows you to extend the maturation time of eggs in females that hatched later. Accordingly, this can increase the number of overwintering eggs within a certain reservoir. This, in turn, increases the number of mature individuals for the next year, and also increases the probability of these eggs being transferred to other reservoirs.\u003c/p\u003e \u003cp\u003eAnother important abiotic factor that can influence the vital activity of \u003cem\u003eB. gaini\u003c/em\u003e is water salinity. On the one hand, salinity stimulates immature and mature Antarctic Fairy Shrimp, but at low concentrations. On the other hand, the ingress of seawater into freshwater reservoirs during storms and an increase in the concentration of salts to 20 psu led to the death of all representatives of this species except for the egg stage (Pociecha and Dumont \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Other scientists confirm that even a slight increase in salinity is a limiting factor for \u003cem\u003eB. gaini\u003c/em\u003e (Hawes et al. \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). This is due to the fact that the cuticle of these crustaceans is permeable for fluids and in salt water the animal begins to lose fluids, which leads to its death. Accordingly, the osmoregulation of \u003cem\u003eB. gaini\u003c/em\u003e shows that it is a classic freshwater species without adaptations to existence at elevated concentrations of salts in water (Ralph \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e1967\u003c/span\u003e);\u003c/p\u003e \u003cp\u003e2) An important reason for the success of \u003cem\u003eB. gaini\u003c/em\u003e in the Antarctic is the almost complete absence of antagonistic interactions in the influence of the biotic factor within the habitat. Anostracans are the largest invertebrates in Antarctic freshwaters that are defenseless against predators. Therefore, their survival strategy is to occupy reservoirs where predators are absent. The main predator that preys on anostracans in different regions of the planet is fish (Ralph \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e1967\u003c/span\u003e), and they live only in marine ecosystems in Antarctica (Trokhymets et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Antarctic freshwater bodies are characterized by an almost complete absence of invertebrate and chordate predators (Laybourn-Parry \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). According to our observations, the only groups of animals that can eat \u003cem\u003eB. gaini\u003c/em\u003e are birds. Other researchers also reported about eat of anostracans by waterfowl (Green et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). We have repeatedly observed how, the South Polar Skua (\u003cem\u003eStercorarius maccormicki\u003c/em\u003e Saunders, 1893) bathed in freshwater ponds and rock pools in the area of ​​the Argentine Islands group. A few times it hunted \u003cem\u003eB. gaini\u003c/em\u003e, but it was more like an instinct when a predator grabs a moving object. This specie of anostracans does not make up a significant part of the bird's diet, and such hunting for small prey is energetically unprofitable.\u003c/p\u003e \u003cp\u003e \u003cem\u003eBranchinecta gaini\u003c/em\u003e is almost devoid of interspecies competition for food and living space in the freshwater bodies of the Antarctic. It competes only for a small part of the food diet (small bacteria and large diatoms) with the copepod \u003cem\u003eB. poppei\u003c/em\u003e (Pociecha and Dumont \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Our research showed that although in a number of cohabitation reservoirs (for example, on Grotto Island) the numbers of copepods were low, but Chi-squared analysis demonstrates the absence of dependence of the presence of \u003cem\u003eB. gaini\u003c/em\u003e in the catch on the presence of \u003cem\u003eB. poppei\u003c/em\u003e in the reservoir.\u003c/p\u003e \u003cp\u003eRegarding the influence of parasites, it is worth mentioning the hymenolepid cestode \u003cem\u003eBranchiopodataenia arctowskii\u003c/em\u003e (Jarecka \u0026amp; Ostas, 1984), for which \u003cem\u003eB. gaini\u003c/em\u003e is an intermediate host (Jarecka \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e1984\u003c/span\u003e). Definitive hosts are seagulls, which consume infected crustaceans. This parasite is not endemic to Antarctica, as it meet in the Northern Hemisphere too (Bondarenko and Kontrymavicius 2004). Unfortunately, there is no information on the infection of \u003cem\u003eB. gaini\u003c/em\u003e populations by this or other parasites in the region of the Wilhelm Archipelago. However, the facts of the South Polar Skua feeding on this crustacean and the presence of the migrating species the Kelp Gull (\u003cem\u003eLarus dominicanus\u003c/em\u003e Lichtenstein, 1823) may indicate the potential presence of this parasite in the crustaceans of this Antarctic region and its possible impact on local anostracan populations;\u003c/p\u003e \u003cp\u003e3) Representatives of \u003cem\u003eB. gaini\u003c/em\u003e are able to enter into a symbiotic relationship with microorganisms. Scientists studied the formation of phyllosymbiosis and the impact on the existence of this type of microbiome that forms on the gills and in the intestines of crustaceans. Microbiomes are assembled through different ecoevolutionary processes stochastically in the gills and deterministically in the gut in each anostracans population. A strong correlation was found between the genetic makeup of \u003cem\u003eB. gaini\u003c/em\u003e and its gut and gill microbiome (Schwob et al. \u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Such symbioses, which are formed as a result of the anostracan interaction with the external environment, can potentially have a positive effect on the survival of sexually mature specimens in an aggressive environment;\u003c/p\u003e \u003cp\u003e4) \u003cem\u003eBranchinecta gaini\u003c/em\u003e is able to exist in reservoirs of different trophic levels. In our research, this species was found in oligotrophic L1 on Uruguay Island, in a number of mesotrophic ponds and rock pools, in eutrophic RP18 on Petermann Island. It is worth noting that this specie was found even in freshwater bodies with a large amount of decomposed and semi-decomposed moss at the bottom (for example, RP14 on Maly Berthelot Island). The main thing is that the free space of the water above the moss remains. This is confirmed by the results of the Mann-Whitney-Wilcoxon test. It indicates that representatives of this species were found more often at a greater depth on average. In general, there are only a few eutrophic reservoirs with the presence of these crustaceans, and they predominate in mesotrophic reservoirs. On the other hand, researchers discovered anostracans in Pond №VII on King George Island in 1977\u0026ndash;1978. This pond is located near a large colony of penguins and their waste products entering the water, it causes eutrophication of the reservoir. As a result of the presence of a large amount of organic matter and the massive development of microalgae, the representatives of the \u003cem\u003eB. gaini\u003c/em\u003e of this reservoir have acquired gigantic sizes. Thus, the maximum body length of females was 28.1 mm, and males \u0026ndash; 29.8 mm (Jurasz et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1983\u003c/span\u003e). This is despite the fact that the standard size of representatives of this species corresponds to 16 mm (Hawes \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). However, the amount of organic matter in the water should not exceed threshold values, since \u003cem\u003eB. gaini\u003c/em\u003e is absent in hypertrophic reservoirs. No crustaceans were found in water bodies with a huge amount of guano during our research on Moot Island (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e15\u003c/span\u003ea). And although only one sample from the pond was examined in laboratory conditions (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e15\u003c/span\u003eb), water was examined in the place for the presence of large-sized crustaceans from more than 10 rock pools located around it (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e15\u003c/span\u003ec\u0026ndash;e);\u003c/p\u003e \u003cp\u003e5) \u003cem\u003eBranchinecta gaini\u003c/em\u003e has a wide range of nutrition and flexible eating behavior. It is characterized by the behavior of scraping off organic matter and transferring it to the oral apparatus with the help of complex manipulations of body appendages. This anostracan can grab pieces of detritus on the bottom half the size of their body and then swim belly up, destroying the detritus with their limbs and manipulating its parts (Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). However, this species is not a narrow detritophagus. The contents of his intestines include the remains of organic sediments and benthic biota was found. Its diet contains a large amount of algae and cyanobacterial mat, which it scrapes from the walls of freshwater reservoirs. Hyphae and spores of fungi, protists, rotifers, tardigrades, parts of the legs of mites, and chironomids, as well as the remains of \u003cem\u003eB. poppei\u003c/em\u003e and \u003cem\u003eB. gaini\u003c/em\u003e, were also found. Thus, \u003cem\u003eB. gaini\u003c/em\u003e is a detritophagous and filter-feeding herbivore that feeds mainly near the bottom on detritus and benthic biota (Paggi \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e1996\u003c/span\u003e). In addition, it is capable of cannibalizing its own dead individuals. Accordingly, it contribute to its own detritus food web, dying before Antarctic winter and providing a food base for the next generation during the following Antarctic summer (Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). It is suggested that \u003cem\u003eB. gaini\u003c/em\u003e may also prey on \u003cem\u003eB. poppei\u003c/em\u003e larvaes (Pociecha and Dumont \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWe observed classic feeding of \u003cem\u003eB. gaini\u003c/em\u003e in P11 on Petermann Island. Transparent water made it possible to visually monitor nutrition. Most of the individuals stayed near the walls and bottom of the reservoir, scraping the cyanobacterial mat and bottom benthos groups from the stones. A few individuals swam belly up with large particles of detritus (pieces of decomposed moss), destroying it with body appendages and directing the detached particles to the mouth apparatus. However, several other individuals swam belly up in the stratum and near the water surface without detritus. They actively moved their limbs and created a flow of water to the front of the body. Therefore, we can make an assumption that they filtered water with suspended organic matter, that is, they fed as planktonic filter feeders. A similar phenomenon was observed in L1 of the Uruguay Island;\u003c/p\u003e \u003cp\u003e6) The survival of \u003cem\u003eB. gaini\u003c/em\u003e in the extreme conditions of the Antarctic is facilitated by the peculiarities of its univoltine life cycle, when only one generation exists during the year. Adaptation to living conditions consists in shortening the development time of active stages and the formation of resting eggs in the difficult conditions of the Antarctic winter. An analysis of the life cycle was conducted on the example of the population of this species from King George Island. Nauplius larvae hatch from resting eggs in November, metanauplius larvae and young individuals develop from them. Development from egg to adult takes place within a month, that is, the first adults appeared in December, and the reproductive period began in January. They laid eggs until mid-May under the ice and died, the reproductive period lasted from January until the water bodies froze. Thus, the active phase of the life cycle lasted from November to May, about six months, and for another six months it experienced adverse conditions in the egg stage. The latter are resistant to low temperatures, lack of oxygen and exposure to ultraviolet radiation, which allows them to survive in freezing water conditions (Jurasz et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1983\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe time and features of the life cycle of \u003cem\u003eB. gaini\u003c/em\u003e can vary according to changes in habitat conditions. Our studies have shown that in the harsher southern conditions of the Wilhelm Archipelago area, the active phase of the \u003cem\u003eB. gaini\u003c/em\u003e life cycle is even more shortened. The period of the beginning of the formation of adults was not in December, but in January, since in December the reservoirs were still covered with ice and in February larvae and juveniles were found in a number of reservoirs next to sexually mature individuals (L1 on Uruguay Island, P8 on Irizar Island, P11 on Petermann Island, etc.). At the same time, freshwater reservoirs began to be covered with ice at the end of March 2020, and already at the beginning of April, the number of living individuals decreased (L1 on Uruguay Island). Thus, the active phase of the life cycle was reduced from 6 months to 4\u0026ndash;5 months. However, the flexibility of the life cycle allowed it to survive in these changing extreme conditions. An interesting feature is that in L1, juveniles prevailed over adults in March 2020. This can be explained by the fact that females lay eggs at different times and eggs laid in a shallow part of the reservoir and subjected to freezing could hatch prematurely, in the year of their laying. This is confirmed by the data of other scientists (Jurasz et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1983\u003c/span\u003e);\u003c/p\u003e \u003cp\u003e7) A key factor to the mastery of \u003cem\u003eB. gaini\u003c/em\u003e in the Antarctic region is the presence of unique eggs that are capable of cryptobiosis and tolerate freezing conditions during the Antarctic winter (Fryer \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e1996\u003c/span\u003e). These eggs are double-shelled (Jurasz et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1983\u003c/span\u003e) and survive freezing to -25\u0026deg;C and desiccation (Peck \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). As a result of mass lying of eggs, their banks are formed, which ensure their mass hatching and distribution. Eggs hatch at positive temperatures, sufficient oxygen concentration in the water and the presence of light (Brendonck \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1996\u003c/span\u003e). Thus, it is the peculiarities of the organization of the eggs that allow this species to survive during freezing water. The eggs can spread with the help of vectors and take over new freshwater bodies. After hatching, these crustaceans quickly develop from larvae to adults, which reproduce and form new egg banks.\u003c/p\u003e \u003cp\u003eIn our opinion, an important factor in the formation of large egg banks of \u003cem\u003eB. gaini\u003c/em\u003e in small freshwater bodies is the formation of large concentrations of adults of this crustacean due to the gradual drying up of small reservoirs and lowering of their water level. We observed a similar phenomenon in RP11 on Grotto Island and in several freshwater bodies in the Palmer Station area (the region of Anvers Island) in 2020;\u003c/p\u003e \u003cp\u003e8) \u003cem\u003eBranchinecta gaini\u003c/em\u003e is characterized by significant morphological and physiological variability between different populations (Pandourski and Evtimova \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2009\u003c/span\u003e) and between different sexes (Jurasz et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1983\u003c/span\u003e; Pociecha \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). Variability contributes to the heterogeneity of a species, which can favor the survival of populations with a particular set of traits in a variable habitat;\u003c/p\u003e \u003cp\u003e9) Finally, the anthropogenic factor increasingly affects the existence and distribution of \u003cem\u003eB. gaini\u003c/em\u003e in freshwater bodies of the Antarctic. For example, plastic pollution of the Maritime Antarctic is gaining momentum. At the same time, both individual species and entire ecosystems suffer from pollution. \u003cem\u003eBranchinecta gaini\u003c/em\u003e was studied for the effect of nanoplastics on them. Studies have shown that nanoplastic affects the growth rate of anostracan molting, changes in the intestinal epithelium, rate of ventilation, and regulation of body functions. The changes occurred at the behavioral and molecular levels. As a result, the researchers concluded that nanoplastics pose a threat to Antarctic biodiversity, and \u003cem\u003eB. gaini\u003c/em\u003e can be used as a model to assess the impact of pollutants on freshwater ecosystems (Bergami et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). \u003cem\u003eBranchinecta gaini\u003c/em\u003e has also been proposed as a biomonitor in the Antarctic due to its sensitivity to nanosized titanium dioxide (n-TiO2). It is a widely used pigment that is present, for example, in paintings and sunscreens (Gonz\u0026aacute;lez-Aravena et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). It is believed that it can also be a bioindicator of oligotrophic ponds (De Los Rios et al. 2008).\u003c/p\u003e \u003cp\u003eThird, the species must have mechanisms of distribution. Therefore, we will consider the main from them for anostracans to freshwater reservoirs of new territories. There are two main distribution strategies (Jocqu\u0026eacute; et al. \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2010\u003c/span\u003e): active dispersers \u0026ndash; able to independently move from one habitat into new habitats; passive dispersers \u0026ndash; need help to move from one habitat into new habitats. \u003cem\u003eBranchinecta gaini\u003c/em\u003e belongs to passive dispersers, since its representatives are not able to actively move in sea water, on land or by air from one freshwater body to another. Passive disperser in the Antarctic is an accidental phenomenon, since \u003cem\u003eB. gaini\u003c/em\u003e entered this continent by random zoophoretic dispersal of eggs by means birds. Similar dispersal by eggs is common in many anostracans (Brendonck \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1996\u003c/span\u003e). Four vectors of passive dispersers can be considered in the Antarctic ecosystems (Hawes \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2009\u003c/span\u003e): anthrochory, hydrochory, anemochory, and zoochory. Next, we will consider the main vectors of the spread of \u003cem\u003eB. gaini\u003c/em\u003e into new Antarctic freshwater bodies:\u003c/p\u003e \u003cp\u003e1) Anthrochory is the dispersal of passive dispersers directly by a person or indirectly with his participation. Although scientists deny this vector of \u003cem\u003eB. gaini\u003c/em\u003e egg transfer (Hawes \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2009\u003c/span\u003e), we will try to express a hypothesis based on personal observations. Over the past decades, there has been an increase in the number of tourists visiting the region of the Wilhelm Archipelago. They have tourist routes, with landings from ships on islands, mostly with penguin colonies and beautiful landscapes. The base point in this region is Petermann Island, through which thousands of tourists pass every year. In the area where the tourist routes pass, there is at least RP18 with anostracans. Potentially, tourists can wash their boots in a pond with crustaceans from the penguin guano, and the bottom sediments are stay on the soles of the shoes. And then everything will depend on the stickiness of the mud. Then the remains of mud with eggs will not be washed from the boots when walking on snow if the stickiness is high. And a person can wash his boots before getting into the boat again and the eggs can get into another freshwater body. Thus, eggs can be transferred from one reservoir to another within one island. Tourists wash their boots on the ship, so further transfer is unlikely. However, tourists often go from one island to another without boarding a ship, for example, from Petermann Island to Great Yalour Island. There is a large colony of other species of penguin. And there can be several such points and at each point people want wash their boots before getting into the boat. If you take tourists on yachts, they land on even more surrounding islands and the probability of accidental contamination is high. The same can be said for inexperienced scientists from different countries, as potentially not all of them thoroughly wash their boots in seawater before getting into the boat. Therefore, in our opinion, the probability of transferring \u003cem\u003eB. gaini\u003c/em\u003e eggs from one freshwater body to another within one island and between different islands is quite high. But this hypothesis needs practical proof;\u003c/p\u003e \u003cp\u003e2) Hydrochory is the dispersal of passive dispersers directly by water. \u003cem\u003eBranchinecta gaini\u003c/em\u003e can stochastic spread by water into freshwater bodies for short distances within one island. This is due to the fact that the reservoirs of this region Antarctic are mostly not connected to each other in a single system. Cascades of bodies of water flowing into each other are registered on Irizar, Eight, and Maly Berthelot Islands. Most of the isolated reservoirs are located in crevices on the slopes of hills or on terraces, and water in them can flow into each other only during the melting of snow and ice. This may be facilitated by the ability of eggs to float to the surface if they are not silted to the bottom of the reservoir (Brendonck and Riddoch \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1999\u003c/span\u003e). Thus, \u003cem\u003eB. gaini\u003c/em\u003e eggs can disperse with the help of water, but not over long distances within a limited area of ​​land.\u003c/p\u003e \u003cp\u003e3) Anemochory is the dispersal of passive dispersers directly by air. Anostracans eggs can be stochastically dispersed by air over short distances between freshwater bodies (Brendonck and Riddoch \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1999\u003c/span\u003e). The spread of eggs over long distances by air is considered unlikely (Vanschoenwinkel et al. \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). This type of dispersal is possible only within shallow rock pools that have time to dry out during the short Antarctic summer. Accordingly, dried sludge with \u003cem\u003eB. gaini\u003c/em\u003e eggs can be carried by the wind over short distances into nearby freshwater bodies. A similar type of distribution could occur, for example, between the reservoirs of Maly Berthelot Island;\u003c/p\u003e \u003cp\u003e4) Zoochory is the dispersal of passive dispersers directly by animals. \u003cem\u003eBranchinecta gaini\u003c/em\u003e can be directed from one reservoir to another over short and long distances by birds (Diaz et al. 2019). It is directional, as a number of waterfowl settle and concentrate near freshwater bodies that are indispensable for birds to drink, bathe, rest, and feed (Viana et al. \u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). The South Polar Skua, Kelp Gull, Antarctic Tern (\u003cem\u003eSterna vittata\u003c/em\u003e Gmelin, 1789), and Snowy Sheathbill (\u003cem\u003eChionis albus\u003c/em\u003e (Gmelin, 1789)) can potentially move \u003cem\u003eB. gaini\u003c/em\u003e eggs in this region of the Wilhelm Archipelago. We only observed the South Polar Skua consuming \u003cem\u003eB. gaini\u003c/em\u003e. Potentially all of these species may consume anostracans, although they do not make up a significant proportion of their diet. This is confirmed by the data of other researchers, for example, they note the consumption of these crustaceans by the Antarctic Tern and South Polar Skua (Nedbalov\u0026aacute; et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Zoochory can manifest itself through epizoochory and endozoochory (Hawes \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eEpizoochory is a type of zoochory, when the dispersal of passive dispersers directly by transfer on the surface of the animal body. \u003cem\u003eBranchinecta gaini\u003c/em\u003e eggs can stick to the feet and feathers of birds along with mud when the latter bathe, drink water or fed. A similar type of distribution is characteristic of other crustaceans (Trokhymets et al. \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). It can occur both between neighboring reservoirs and over long distances between islands. A similar distribution is highly likely for most freshwater bodies, as the South Polar Skua and other birds nest and inhabit almost all islands in the Wilhelm Archipelago area. They fly long distances to other groups of islands and the continental coast during hunting. We watched the South Polar Skua fly from Locator Island towards Galindez Island for a distance of about 13 km and then return within a few hours.\u003c/p\u003e \u003cp\u003eEndozoochory is a type of zoochory, when the dispersal of passive dispersers directly by transfer inside the animal's digestive system. Similar transportation of anostracans eggs occurs by accidental ingestion of them into the digestive system of animals while drinking water or by targeted consumption of female crustaceans with viable eggs. Thus, eggs can be safely transported in the digestive system of birds during long-distance flights and, after bird excretion, enter new freshwater bodies (Green and Figuerola \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Rogers \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). In other regions of the planet, insects (Beladjal and Mertens \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2009\u003c/span\u003e), fish (Beladjal et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2007\u003c/span\u003e), amphibians (Bohonak and Whiteman \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e1999\u003c/span\u003e), and birds (Green et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2005\u003c/span\u003e) are capable of carrying anostracans eggs in the digestive system. However, most of the predators capable of hunting anostracans in the Antarctic are absent. Therefore, only birds can carry \u003cem\u003eB. gaini\u003c/em\u003e eggs in their own digestive system. We have already provided a list of bird species potentially capable of spreading anostracans eggs by zoochory. Other scientists also identify some of these birds as possible vectors for the spread of this crustacean species (Hawes \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Nedbalov\u0026aacute; et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Thus, endozoochory (as well as epizoochory) is one of the main ways of spreading \u003cem\u003eB. gaini\u003c/em\u003e over short and long distances within the Wilhelm Archipelago.\u003c/p\u003e \u003cp\u003eAs a result of our research, we can conclude that \u003cem\u003eB. gaini\u003c/em\u003e is found in reservoirs with cyanobacterial mats on the walls and detritus on the bottom, it need water space (it were also found at a depth of 0.1 m, but they preferred reservoirs with a greater depth), the presence of birds for zoochory, but absent around large penguin colonies. As for distribution in the Wilhelm Archipelago region, this species has a wide range of vectors, but the most common variants are zoochory and hydrochory.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u0026nbsp;\u003c/strong\u003eThe authors express their gratitude to the National Antarctic Scientific Center of Ukraine (Ministry of Education and Science of Ukraine) for funding and organizing the Ukrainian Antarctic Expeditions, during which collection and analysis of specimens were conducted. We are also grateful to the Taras Shevchenko National University of Kyiv for fully supporting this study. The authors acknowledge Natural Earth, SCAR (Antarctic Digital Database) and UK Polar Data Centre for providing access to map databases for non-commercial use. We would like to dedicate this article to the Ukrainian people.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003eVT conceived the study; VT, PDLRE, AZ, and ID wrote the manuscript; VT and ID conducted field and lab work. All authors effectively contributed to the interpretation of findings and revision, and editing of the final draft of the article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest and ethics approval.\u0026nbsp;\u003c/strong\u003eAll authors declare that they have no conflicts or competing interests and that the study was conducted according to the requirements of their national research committee.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability.\u0026nbsp;\u003c/strong\u003eAll data are presented in the main manuscript and supplementary table (related file).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBargagli R (2020) Terrestrial ecosystems of the Antarctic Peninsula and their responses to climate change and anthropogenic impacts. UAJ 2:84\u0026ndash;97. https://doi.org/10.33275/1727-7485.2.2020.656\u003c/li\u003e\n\u003cli\u003eBauer DF (1972) Constructing confidence sets using rank statistics. 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Br Antarct Surv Bull 40:37\u0026ndash;47\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Zoogeography, Branchiopods, Freshwater crustaceans, Antarctic","lastPublishedDoi":"10.21203/rs.3.rs-6255807/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6255807/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe anostracan \u003cem\u003eBranchinecta gaini\u003c/em\u003e is the largest animal, the main consumer of detritus and benthos, and a background species of energy harvester in the trophic food chains of Antarctic freshwater bodies. This crustacean species was first recorded in the freshwater reservoir of Petermann Island (Wilhelm Archipelago, Maritime Antarctica) during the Second French Antarctic Expedition of Jean-Baptiste Charcot in 1909. This work aimed to investigate the current distribution and its mechanisms of \u003cem\u003eB. gaini\u003c/em\u003e in the Argentine Islands of this archipelago. \u003cem\u003eBranchinecta gaini\u003c/em\u003e was found during our research within the freshwater bodies of Uruguay and Galindez Islands in 2007. In addition, this species was registered in reservoirs of three islands in 2008, six islands in 2010, and nine islands in 2020. As a result, \u003cem\u003eB. gaini\u003c/em\u003e was found in the 32 freshwater bodies of 12 islands in the Wilhelm Archipelago region and for the first time in reservoirs of 11 islands. Different ways and mechanisms of the distribution of \u003cem\u003eB. gaini\u003c/em\u003e in extreme Antarctic conditions were also considered.\u003c/p\u003e","manuscriptTitle":"Distribution and its mechanisms of Branchinecta gaini (Branchiopoda: Anostraca) in the area of the Wilhelm Archipelago (Maritime Antarctica)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-22 19:17:03","doi":"10.21203/rs.3.rs-6255807/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9bc20fd5-fb58-4a5c-ac62-6a2cf1b9f87c","owner":[],"postedDate":"April 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-08-21T16:08:35+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-22 19:17:03","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6255807","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6255807","identity":"rs-6255807","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}