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

Distribution 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 of Branchinecta gaini (Branchiopoda: Anostraca) in the area of the Wilhelm Archipelago (Maritime Antarctica) Vladlen Trokhymets, Ihor Dykyy, Karel Janko, Artem Zinkovskyi, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7830481/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract The anostracan Branchinecta gaini is the largest invertebrate animal in Antarctic freshwater bodies. This crustacean species playing important role in Antarctic ecosystems, was first recorded in the freshwater ponds of Petermann Island (Wilhelm Archipelago, Maritime Antarctica) during the Second French Antarctic Expedition of Jean-Baptiste Charcot in 1909. More complete official information about the distribution of this crustacean within this region of Antarctica is almost absent. Thus, present work aims to investigate the current distribution of B. gaini in the region of Argentine Islands – southern part of this archipelago. During multiyear sampling effort covering 2007, 2008, 2010 and 2020 expeditions, Branchinecta gaini was found in 32 freshwater bodies of 12 islands of the Wilhelm Archipelago region and for the first time in reservoirs of 11 islands. Zoogeography Branchiopods Freshwater crustaceans Antarctica 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 living organisms, particularly in terrestrial ecosystems (Convey 2017 ). Unlike the relatively stable marine environment, terrestrial habitats experience strong daily and seasonal fluctuations in environmental variables such as temperature. As a result, terrestrial biota must show high physiological and ecological flexibility to survive (Peck 2005 ). There is general consensus that most species inhabiting Antarctica are long-term endemic lineages that have adapted to these harsh conditions over millions of years. However, current rapid warming is altering these ecosystems, potentially expanding species’ ranges, increasing population sizes and productivity, reshaping community structure, and allowing the introduction of non-native species (Convey and Peck 2019 ). Freshwater reservoirs – both permanent and temporary (lakes, ponds, and rock pools) – play a special role in Antarctic terrestrial ecosystems. Among these, small water bodies are the most common, with rock pools predominating (Hawes et al. 2011 ). These pools represent some of the oldest and most extreme temporary habitats (Brendonck and Riddoch 1999 ). Worldwide freshwater rock pools host about 460 animal species. Antarctic rock pools are remarkable for their exceptionally high faunal diversity: they contain 42 genera of active dispersers and 41 genera of passive dispersers (Jocqué et al. 2010 ). By comparison, North American rock pools support only 32 and 14 genera with the same dispersal strategies, respectively (Jocqué et al. 2010 ). In Antarctic freshwater ecosystems, biodiversity and biomass are primarily supported by cyanobacteria and plants, while animals contribute to ecosystem stability. Among animals, benthic and planktonic forms dominate across taxonomic groups (Gibson et al. 2006 ). Altogether, 336 invertebrate taxa (species, genera, and higher-level groups) have been recorded in Antarctic freshwater bodies, with 121 known from Maritime Antarctica (Dartnall 2017 ). Crustaceans account for 66 taxa, nine of which occur in the Maritime Antarctic. On the Antarctic Peninsula, only four freshwater crustacean species have been reported: two branchiopods and two copepods (Diaz et al. 2019; Trokhymets et al. 2021 ). The class Branchiopoda Latreille, 1817 currently includes about 500 species. Anostracans, one of its major groups, occur mainly in temporary freshwater habitats, although some species inhabit saline waters. Most anostracans are omnivorous filter feeders, though predatory species are also known (Brendonck et al. 2008 ). They withstand unfavourable conditions by producing resting egg (“cyst”) banks (Brendonck 1996 ). Anostracans are relatively large branchiopods, and many new species have been described in recent decades (Rogers and Ferreira 2007 ). Their known diversity has increased from 258 species in 1993 (Belk and Brtek 1995 ) to about 300 species in 2008 (Brendonck et al. 2008 ), a growth partly explained by the fact that nearly 25% of species are known only from their type localities (Belk and Brtek 1995 ). The genus Branchinecta Verrill, 1869 (family Branchinectidae Daday, 1910) is the only group of anostracans occurring in Antarctic freshwater bodies. It currently includes about 48 species, distributed across most continents except Australia (Rogers et al. 2020b ; Beladjal and Mounia 2023 ; Evtimova et al. 2024 ). The Antarctic fairy shrimp, Branchinecta gaini Daday, 1910, is the sole anostracan species recorded in Antarctic freshwater habitats (Rosenfeld et al. 2023 ). It was first discovered on Petermann Island (65°10′34″S, 66°32′30″W) and nearby small islands of the Wilhelm Archipelago during the Second French Antarctic Expedition, led by Jean-Baptiste Charcot, when Mr. L. Hein collected specimens in 1909 (Daday de Deés 1910). For many years, B. gaini was thought to be widespread, with records from southern South America (De Los Ríos et al. 2008 ; Rogers et al. 2008 ; De Los Ríos-Escalante and Kotov 2015 ), the Falkland Islands (Weller 1975 ; Hawes 2009 ; Diaz et al. 2019), South Georgia (Dartnall and Heywood 1980 ; Dartnall 2005 , 2017 ), the South Orkney Islands (Brendonck et al. 2008 ; Dartnall 2017 ; Diaz et al. 2019), the South Shetland Islands (Janiec 1996 ; Toro et al. 2006 ; Rochera and Camacho 2019 ), and the Antarctic Peninsula (Björck et al. 1996 ; Nedbalová et al. 2017 ; Maturana et al. 2025 ). According to this interpretation, B. gaini coexisted in Patagonia with the morphologically similar Branchinecta granulosa Daday, 1902 (Linder 1941 ; Rogers et al. 2008 ). Several reports even listed B. granulosa from Antarctica (Bryant 1945 ; Polishuk et al. 2009 ), but most authors rejected these as misidentifications of B. gaini (Pugh et al. 2002 ; Hawes 2009 ; Rogers et al. 2020a ). The presence of B. gaini in South America and the Falkland Islands has likewise been questioned (Pugh et al. 2002 ; Rogers et al. 2020a ). Subsequently, Rogers et al. ( 2020b ) argued that all Patagonian records of B. gaini in fact belong to B. granulosa , and that the distribution of B. gaini is restricted to Antarctica and adjacent islands. Comparative molecular and phylogenetic analyses published in 2024 further revealed minimal genetic differentiation between the two species, raising the possibility that they represent a single taxon with slight morphological variation among populations (Pokorný et al. 2024 ). Thus, two main interpretations exist: (1) B. granulosa and B. gaini are separate species, restricted to South America and Antarctica (plus adjacent islands), respectively, with Falkland Island populations requiring further study; or (2) B. granulosa and B. gaini are conspecific. In this publication, we adopt the more widely accepted first view (Fig. 1 ) but emphasize the need for further research. If B. gaini proves invalid, all Antarctic and sub-Antarctic records would need to be reclassified as populations of B. granulosa . Research on B. gaini in the Wilhelm Archipelago has remained fragmentary since its first discovery by L. Hein in 1909 (Daday de Deés 1910). Most records come from scattered references by English and Ukrainian researchers, unpublished reports, and a few publications (Polishuk et al. 2009 ; Chernov et al. 2020 ). In these accounts, the species was often identified as B. granulosa , with findings reported from several islands (Galindez, Skua, Mitina, and Uruguay), usually without precise coordinates or descriptions of the freshwater bodies. Subsequent revisions reassigned these records to B. gaini (Chernov et al. 2021 ; Trokhymets and Dykyy 2021 ). However, detailed data on its local distribution within the Wilhelm Archipelago are still lacking. The aim of this study is therefore to provide a comprehensive assessment of the occurrence and distribution of B. gaini in the Wilhelm Archipelago, based on new field records and analyses. Materials and methods Place and date of material collection Samples were collected from freshwater bodies in the Wilhelm Archipelago region. We followed the classification of freshwater bodies proposed by Trokhymets et al. ( 2024 ): Lakes – do not freeze to the bottom, depth > 2 m, surface area ≥ 100 m²; Ponds – freeze to the bottom in winter, depth < 2 m, surface area 10–100 m² (or larger, but shallow); Rock pools – freeze to the bottom in winter, depth ≤ 1 m, surface area < 10 m². Samples were collected during several Ukrainian Antarctic Expeditions: 12th Expedition (March 2007) – 8 samples from freshwater bodies of four islands and Cape Rasmussen, 12th Expedition (January–February 2008) – 7 samples from six islands, 14th Expedition (January–March 2010) – 18 samples from 12 islands and Cape Rasmussen, 25th Expedition (February–April 2020) – 111 samples from 20 islands and three continental capes. Table 1 lists freshwater bodies where B. gaini was recorded, with GPS coordinates; Table 2 lists those where it 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 RP, 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. RP, RP 65°07'09.6"S 64°04'24.3"W, 65°07'01.8"S 64°04'20.6"W 2020 Pléneau Is. RP 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 * RP 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. RP 65°14'53.2"S 64°15'51.3"W 2020 Skua Is. RP, 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.* RP, 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 taken using a 2-liter water sampler. Volumes of 5–20 L were filtered through a 100 µm conical plankton net (Janiec 1991 ; Burian and Trokhymets 2017 ). If fairy shrimp were visible but not captured in the plankton samples (due to low abundance), they were collected directly with a hand net (Jo et al. 2022 ). This approach allows quantitative assessment of copepods, but only qualitative (presence/absence) assessment of fairy shrimp, as their behaviour and patchy distribution make quantitative sampling unreliable (Pociecha and Dumont 2008 ). Specimens were preserved in 99% ethanol for molecular analyses (Pokorný et al. 2024 ) and in 4% formaldehyde for morphological study (Pociecha and Dumont 2008 ). Salinity was measured with a salinity meter, and water temperature with a mercury thermometer. Taxonomic identification Samples from 2007–2010 were analyzed in the laboratory of the Educational and Scientific Center “Institute of Biology and Medicine”, Taras Shevchenko National University of Kyiv. Samples from 2020 were studied at the Ukrainian Antarctic Akademik Vernadsky Station. Morphological examinations were carried out with an MBS-12 stereomicroscope. Adult B. gaini were identified based on structural characters of the second antenna, gonopodia, and male genital segments (Daday de Deés 1910; Jurasz et al. 1983 ; Rogers et al. 2020a ). Larvae were identified using published illustrations of the life cycle (Jurasz et al. 1983 ). Different developmental stages of B. gaini are shown 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 Normality of data was tested with the Shapiro–Wilk test, which indicated non-normal distributions. Therefore, the nonparametric Mann–Whitney–Wilcoxon test (Bauer 1972 ) was applied to assess the effect of depth, salinity, and temperature on the presence of B. gaini . Pearson’s chi-squared test (Pearson 1900 ) was used to evaluate the influence of cyanobacterial mats, presence of Boeckella poppei (Mrázek, 1901; Copepoda, Calanoida), and sampling time (month, year) on the presence of B. gaini . Analyses included only freshwater bodies located on islands where B. gaini has previously been recorded (either in earlier studies or in the present work). Although suitable habitats exist on other islands, there is currently no evidence of colonization, and including them would bias the results. All analyses were performed in RStudio v1.4.1106 with R v4.0.5. Results Branchinecta gaini was recorded in two freshwater bodies on Uruguay and Galindez Islands (out of four islands and Cape Rasmussen examined) in 2007; in three reservoirs on three islands (out of six examined) in 2008; in six freshwater bodies on six islands (out of 12 examined) and Cape Rasmussen in 2010; and in 27 reservoirs on nine islands (out of 20 examined) and three continental capes in 2020 (Tables 1 , 2 ). Some sites, such as Galindez Island, were sampled repeatedly in different years, so the total number of islands with B. gaini records is not a simple sum across years. In total, B. gaini was found in 32 freshwater bodies on 12 islands of the Wilhelm Archipelago (Fig. 3 ). Eleven of these islands yielded records of the species for the first time. Below, we describe in detail the reservoirs and islands where B. gaini was recorded. 1. Uruguay Island belongs to the Argentine Islands group of the Wilhelm Archipelago (Fig. 4 a). It lies in the Bellingshausen Sea, 2 km northeast of Galindez Island and about 6 km from the coast of the Kyiv Peninsula. The island consists of northern and southern parts connected by a narrow isthmus. The pond P1 is located in the southern part of the island, on the left side of the central rocky ridge when moving from south to north (Fig. 4 b). It lies at an altitude of 15 m a.s.l., measures about 50 × 20 m, and reaches a depth of 1.5 m. The bottom is rocky, with patches of brown cyanobacterial mat on the walls. One adult B. gaini was recorded in March 2007. A resample in April 2020 yielded no individuals, likely because the pond was covered with a 5 cm layer of ice at the time; a hole had to be drilled to collect the sample. It is probable that adults had already died after laying overwintering eggs. The pond P9 is located on the southern part of the island, on the right side of the central rocky ridge (Fig. 4 c), at an altitude of 11 m a.s.l. It measures approximately 120 × 50 m and is up to 0.7 m deep. The bottom is rocky and the walls bear patches of brown cyanobacterial mat. Several adult B. gaini were recorded beneath a thin ice cover in April 2020. The lake L1, the elongated depression, is located in the centre of the northern part of the island (Fig. 4 d–e). It is situated at 40 m a.s.l., measuring about 300 × 80 m with a maximum depth of 8 m in its northern part. L1 is the largest lake in the Argentine Islands. Its stony bottom is partly covered with green organic matter, and the walls with a thin cyanobacterial mat. It is one of the few reservoirs in the region that does not freeze to the bottom in winter, allowing aquatic fauna to remain active throughout the coldest season. L1 is hydrologically connected by channels to a subglacial lake beneath a 12 m thick ice dome, with a depth of 9 m. During thermal drilling of the ice dome, fragments of B. gaini limbs were found (Chernov et al. 2020 ), confirming the connection. However, as B. gaini is not a troglobiont, its survival in a closed subglacial ecosystem is highly unlikely. L1 therefore represents a unique ecosystem where typical Antarctic freshwater organisms may coexist with species occasionally transferred from the subglacial environment. Previously, L1 was proposed as Base Station №2 for continuous monitoring of B. poppei (Trokhymets et al. 2024 ). We further propose that L1 should serve as “Basic Freshwater Hydrobiological Station №1” for permanent monitoring of hydrobionts, and also as Base Station №2 for long-term monitoring of B. gaini and B. poppei in this part of the Wilhelm Archipelago (Table 3 ). 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 Branchinecta gaini was recorded in L1 in February 2010 and March 2020. In 2010, 19 individuals were collected (nine females, four males, and six juveniles). In 2020, 13 individuals were collected (three females and 10 juveniles). Weekly monitoring from March 10 to April 14, 2020, showed that B. gaini was consistently present, although numbers declined; the final sample (April 14) contained three live individuals (one female, two males) and one dead specimen. 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. The pond P2 lies near the island’s highest point (Fig. 5 b–c). Although morphologically similar to a rock pool, it is classified here as a pond. It has a roughly circular shape, measuring about 4 × 4 m with a depth of up to 30 cm. The walls are coated with a 1 mm thick brown cyanobacterial mat. Branchinecta gaini was consistently recorded in P2 during all four years of study: March 2007 (12 adults), February 2008 (10 adults), January 2010 (9 adults), and February 2020 (15 adults). This is the only freshwater body where the species was detected in every sampling year. We therefore propose P2 as Base Station №3 for long-term monitoring of B. gaini population dynamics. Additionally, we suggest relocating Base Station №3 for monitoring of B. poppei from Grotto Island (Trokhymets et al. 2024 ) to Galindez Island (Table 3 ), where a new population of this copepod was recently identified (Nabokin et al. 2023 ). The rock pool RP19 lies on the top of a flat hill. It measures 3 × 3 m with a depth of up to 0.3 m. The bottom is rocky and covered with organic matter, while the walls bear a brown cyanobacterial mat. At the time of sampling, the water was opaque due to a phytoplankton bloom. In March 2020, 23 sexually mature B. gaini were recorded. 3. Skua Island belongs to the Argentine Islands group (Fig. 6 a). It is located in the Bellingshausen Sea, 0.7 km southwest of the Ukrainian Antarctic Akademik Vernadsky Station on Galindez Island and about 6 km from the coast of the Kyiv Peninsula. The rock pool RP1 lies on a slope terrace along the southwest coast of the island. It has an elongated polygonal shape, measuring 2 × 1 m with a depth of 0.3 m. The stone bottom is partly covered with green-brown organic matter, while the walls are overgrown with a 1 mm thick brown cyanobacterial mat (Fig. 6 b). Seven sexually mature B. gaini were recorded here in February 2008. The Lake 2 (L2) is one of the largest freshwater bodies in the Wilhelm Archipelago is also located on Skua Island (Fig. 6 c). It lies in the northern part of the island, near the ice dome and several stone hills (65°15′10″S, 64°15′40″W). For much of the year, the reservoir remains ice-covered, making its full extent difficult to determine. However, during maximum thawing in February–March 2020, its approximate size was estimated at 200 × 85 m, with a depth exceeding 2 m. Based on these dimensions, it is classified as a lake. No crustaceans were detected by visual inspection in 2020, and detailed analysis of the aquatic fauna was not possible at that time. Future studies will be needed to assess colonization processes in this reservoir. Its proximity to Galindez Island makes it particularly convenient for long-term ecological monitoring. We therefore propose this lake as Basic Freshwater Hydrobiological Station №2 for permanent monitoring of hydrobionts (Table 3 ). 4. Mitina Island (unofficial name, currently unnamed) is part of the Barchans subgroup of the Argentine Islands (Fig. 7 a). It is the northeastern island of the Barchans, situated in the Bellingshausen Sea, 2 km west of Galindez Island and about 8.5 km from the continental coast of the Kyiv Peninsula. The pond P3 is located on a stone plateau along the northwestern coast of the island, at an elevation of 12 m a.s.l. (Fig. 7 b). It has an irregular quadrangular shape with unequal sides, measuring 4 × 3 m and up to 0.3 m deep. The stony bottom contains accumulations of semi-decomposed moss in the deepest part, and the walls and bottom are coated with a thin brown cyanobacterial mat. Branchinecta gaini was recorded here in February 2008 (14 sexually mature individuals), February 2010 (7 individuals), and February 2020 (24 individuals). 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. The pond P4 lies in the northern part of the island, at the base of a narrow peninsula extending northeastward. It was formed on a stone terrace near a hill, with scattered stone blocks shaping it into a polygonal depression (Fig. 8 b–c). The pond covers an area of about 12 m² and has a depth of 0.4 m. Its bottom contains an accumulated layer of semi-decomposed moss, while the walls are coated with a cyanobacterial mat. Three sexually mature B. gaini were recorded here 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). The pond P5 is situated on the northeastern part of the island at an elevation of 7 m a.s.l. (Fig. 9 b). It occupies a stone gorge and has an L-shaped outline, measuring 7 × 2 m with a depth of 0.4 m. The rocky walls are covered with a thick brownish-red cyanobacterial mat (Fig. 9 c), and the bottom contains a small amount of silt from decomposed moss. Twenty sexually mature B. gaini were recorded here in March 2010. The rock pool RP18 is located in the southern coastal part of the island at 8 m a.s.l. (Fig. 9 d). It has an irregular shape resembling a cross, with dimensions of 3 × 2 m and a depth of 0.3 m. It lies in a hollow on a slope between large stone blocks. The walls are coated with a thin brown cyanobacterial mat, while the bottom holds several centimetres of silt and partially decomposed moss. Fifteen adult B. gaini were recorded here in February 2020. This reservoir is unique in our study as it appears to be strongly influenced by local avifauna. Small colonies of Gentoo penguins ( Pygoscelis papua ) are situated just tens of meters above and below RP18. As a result, feathers and guano enter the pond with meltwater, making the water opaque and leaving feathers floating on the surface. RP18 is less polluted than reservoirs located directly within the penguin colony, where crustaceans have never been found. The pond P11, rhomboid in shape, lies in the northern part of the island at an elevation of 16 m a.s.l. (Fig. 9 e). It occupies a stone hollow, measuring 5 × 3 m with a depth of up to 0.4 m. The walls are coated with a thin brown cyanobacterial mat to a depth of 30 cm, and the bottom contains some silt from decomposed moss. During visual inspection in February 2020, numerous anostracans were observed grazing on the cyanobacterial mats covering the stones. In the sample, 62 individuals were recorded (56 adults, one juvenile, and five larvae). 7. Winter Island is part of the Argentine Islands group (Fig. 10 a). It lies in the Bellingshausen Sea, only 0.15 km from the Ukrainian Antarctic Akademik Vernadsky Station on neighboring Galindez Island and about 6.5 km from the continental coast of the Kyiv Peninsula. The rock pool RP2 has an oval shape and is located near the coast, opposite Skua Island (Fig. 10 b). It occupies a hollow between stone blocks, measuring 3 × 2 m with a depth of 0.4 m. The walls are coated with a thin brown cyanobacterial mat, while the gravel bottom holds a 5 cm layer of decomposed and semi-decomposed moss. Three adult B. gaini were recorded here in February 2010. 8. Irizar Island belongs to the Argentine Islands group (Fig. 11 a). It lies in the Bellingshausen Sea, 3.5 km northeast of Galindez Island and about 6 km from the continental coast of the Kyiv Peninsula. The pond P6, elongated polygonal, is located on a terrace along the northernmost rocky ridge of the island, at 15 m a.s.l. (Fig. 11 b). It measures 6 × 2 m with a depth of 0.5 m. The stone walls are coated with a thin brown cyanobacterial mat, and the bottom contains a 0.1 m layer of decomposed and semi-decomposed moss silt. Seven sexually mature B. gaini were recorded here in February 2020. P6 was designated Base Station №1 for long-term monitoring of the phenology of B. gaini and B. poppei (Trokhymets et al. 2024 ; Table 3 ). The rock pool RP3 lies near the shore, slightly east of P6, in a terrace depression at 12 m a.s.l. It has a triangular shape, measuring 1.5 × 0.5 m with a depth of 0.3 m. The stone walls and bottom are coated with a thin cyanobacterial mat. Two adult B. gaini were recorded in February 2020. The rock pools RP4 and RP5 are located north of P6 (Fig. 11 c). RP4 is spindle-shaped, situated on a rock terrace at 14 m a.s.l., measuring 2 × 1 m with a depth of 0.3 m. RP5 lies a few meters higher (15 m a.s.l.) and has a quadrangular shape, measuring 2 × 1.5 m with a depth of 0.4 m. Both ponds have walls coated with a thin brown cyanobacterial mat, and their bottoms contain a thin layer of decomposed moss. Five and six sexually mature B. gaini were found in RP4 and RP5, respectively, in February 2020. The pond P7 occupies a terrace on the rock slope at 12 m a.s.l., northwest of the other reservoirs. It has an irregular quadrangular outline, measuring 10 × 3 m with a depth of 1 m. The stone walls are covered with a thin brown cyanobacterial mat, while the bottom is free of silt. One adult B. gaini was recorded here in March 2020. The pond P8, round in shape, lies on a terrace of one of the island’s hills, at 21 m a.s.l. (Fig. 11 d). It measures 20 × 20 m with a depth of 1 m. The walls are coated with a thin brown cyanobacterial mat extending 30 cm deep, while the stony bottom contains a thin layer of silt from decomposed moss. Seven B. gaini larvae and juveniles were detected in February 2020. This was the only freshwater body on the island where early developmental stages were observed; no adults were present. The rock pool RP6 lies in a depression on a rock slope at 8 m a.s.l. It measures 2 × 1.5 m with a depth of 0.3 m. The walls are coated with a thin brown cyanobacterial mat, and the stony bottom has patches of decomposed moss. At the time of sampling, the reservoir was already covered by 3 cm of ice. Three adult B. gaini were recorded in March 2020. 9. Eight Island (unofficial name, an officially unnamed) is part of the Argentine Islands group (Fig. 12 a). It lies in the Bellingshausen Sea, 3 km northeast of Galindez Island and about 6 km from the continental coast of the Kyiv Peninsula. The island consists of northern and southern parts connected by an isthmus. Samples were collected in the southern part. The rock pool RP7 is located on a terrace of the northern slope, at 8 m a.s.l. (Fig. 12 b). It has a triangular shape, with its base lying under ice and its sharp corner pointing downslope. It measures 3 × 2 m and is up to 0.3 m deep. The stone walls are coated with a thin cyanobacterial mat, and the bottom contains silt from semi-decomposed moss. Excess water flows downslope, forming a cascade of small rock pools where crustaceans were also present. As this represents a single connected system, these rock pools were not considered separate reservoirs. Five sexually mature B. gaini were recorded in RP7 in February 2020. In the same area, several smaller, isolated rock pools were found, three of which (the rock pools RP8–10) contained B. gaini . These reservoirs have rounded or polygonal shapes, measuring 2–1 × 1–0.5 m with depths of 0.2–0.3 m (Fig. 12 c). Their walls and bottoms are covered with cyanobacterial mats. In February 2020, several adults of B. gaini were recorded: three in RP8, two in RP9, and two in RP10. 10. Grotto Island is part of the Argentine Islands group (Fig. 13 a). It lies in the Bellingshausen Sea, 0.4 km north of Galindez Island and about 7 km from the continental coast of the Kyiv Peninsula. The rock pool RP11 is elongated and located on the northwest coast of the island, 20 m from the shore, at 5 m a.s.l. It measures 10 × 1 m with a depth of 0.4 m and lies in a gap between large stone blocks (Fig. 13 b). The stone walls and bottom are covered with a 2 mm thick brown cyanobacterial mat, with patches of silt from decomposed moss on the bottom. Seventy sexually mature B. gaini were recorded in March 2020 from the deepest part of RP11. Rock pools RP12 and RP13 – two smaller ponds are located nearby (Fig. 13 c). RP12 measures 4 × 2 m, while RP13 is 2 × 1 m. Both have irregular polygonal shapes and depths of 0.2–0.3 m. Their walls are coated with thin cyanobacterial mats, which reached 2 mm in places. In March 2020, 11 adult B. gaini were recorded in RP12 and five in RP13. Other shallow rock pools occur in the area, but those with abundant semi-decomposed moss did not contain anostracans. 11. Maly Berthelot Island (unofficial name, an officially unnamed) is part of the Berthelot Islands group (Fig. 8 a). It lies in the Bellingshausen Sea, 11 km southeast of Galindez Island and about 5 km from the continental coast of the Kyiv Peninsula. The pond P10, elongated in shape, is located on an elevation in the northern part of the island, at 39 m a.s.l. (Fig. 8 d). It measures 20 × 5 m with a depth of 0.5 m. The stony bottom is partly covered with decomposed and semi-decomposed moss, while the walls bear patches of brown cyanobacterial mat up to 2 mm thick. Eighty-three adult B. gaini were recorded here in March 2020. Rock pool RP14 lies on the central highlands of the island at 41 m a.s.l. It has a shape resembling the letter W, measuring 5 × 2 m with a depth of 0.2 m. The stony bottom is covered with decomposed and semi-decomposed moss. Along the pond margins, moss fills the space from bottom to surface, leaving only a central opening of free water where anostracans concentrate. The walls are coated with a thick brown cyanobacterial mat. Several smaller rock pools (RP15–17) are located nearby. They vary in shape, measure only a few square meters, and reach depths of up to 0.2 m. Their stone bottoms hold semi-decomposed moss, and their walls are covered with cyanobacterial mats. In March 2020, sexually mature B. gaini were recorded in all four ponds: 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. The pond P12 is situated on the western part of the island, 15 m inland from the shore, at 5 m a.s.l. It measures 10 × 4 m with a depth of up to 0.4 m. The stone walls and the bottom (to a depth of 30 cm) are coated with a 2–3 mm thick brown cyanobacterial mat. The bottom also contains abundant silt from decomposed moss (Fig. 14 b), while semi-decomposed and fresh moss occur near the shore. In February 2020, 37 B. gaini individuals were recorded here (28 adults and 9 juveniles). The influence of environmental and biotic factors on the occurrence of B. gaini was evaluated using nonparametric tests. The Mann–Whitney–Wilcoxon test indicated that depth significantly affected the likelihood of encountering B. gaini (Table 4 ). On average, the species was found more frequently in deeper water bodies. Nevertheless, B. gaini was present across the full depth range studied (0.1–1.0 m), although it was recorded only once at the shallowest depth of 0.1 m. In contrast, water temperature and salinity had no significant effect on the probability of occurrence; both variables showed only narrow ranges of variation across the studied sites. 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 analyses revealed no significant association between the presence of B. gaini and the presence of B. poppei (_χ²_1 = 2.797, p = 0.0944), month of sampling (_χ²_3 = 0.853, p = 0.3557), or year of sampling (_χ²_3 = 3.416, p = 0.0646). In contrast, the presence of cyanobacterial mats had a significant positive effect on the occurrence of B. gaini (_χ²_1 = 4.255, p = 0.0391). However, this result should be interpreted with caution, as reservoirs lacking mats were rare (n = 6), and B. gaini was absent from all of them. Discussion We investigated the distribution of B. gaini in freshwater reservoirs across the islands and capes of the Antarctic coast within the Wilhelm Archipelago. Our study area extended ~ 25 km north–south (Hovgaard Island to the Berthelot Islands) and ~ 22 km west–east (Cruls Islands to the continental coast), enabling us to obtain new data on the freshwater fauna of this Antarctic region. Long-term surveys showed that the number of reservoirs and islands with B. gaini records increased over time (years: 2007 → 2008 → 2010 → 2020; reservoirs: 2 → 3 → 6 → 27; islands: 2 → 3 → 6 → 9). Although some islands and reservoirs were resampled across years, the overall trend remains. This pattern reflects increased sampling effort (studied reservoirs: 8 → 7 → 18 → 111; studied islands/capes: 5 → 6 → 13 → 23). An important driver of new records was the work of hydrobiologists at the Ukrainian Antarctic Akademik Vernadsky Station on Galindez Island: the first author’s surveys in 2007–2008 effectively initiated modern research on this crustacean in the region, which then expanded. Because B. gaini was first described in 1910 from Petermann Island and nearby islets of the Wilhelm Archipelago (Daday de Deés 1910), rapid colonization during only the 14 years of our study (2007–2020) is unlikely; rather, the species has had ~ 100 years to occupy suitable habitats (Polishuk et al. 2009 ; Chernov et al. 2020 ). On the other hand, we did not detect B. gaini on 15 surveyed islands/capes that appear environmentally suitable, and even on islands with records, some water bodies lacked the species. Overall, B. gaini is a common regional species that appears to be gradually expanding within available habitats. To interpret the current distribution of the southernmost anostracan, we first consider the species’ origin in Antarctica (Rogers et al. 2020b ). Two hypotheses have been discussed: (i) Antarctic endemism and (ii) colonization from other regions. Most authors reject strict endemism because resting eggs are unlikely to remain viable through centuries of freezing, and because the active life-cycle phase of B. gaini occurs in summer under liquid water and positive temperatures (Jurasz et al. 1983 ). This seasonal activity is supported by the species’ metabolic eurythermy (Peck 2004 ; Pociecha 2007 ) and contrasts with many Antarctic terrestrial invertebrates that have slow life cycles. Thus, B. gaini is not a classic Antarctic specialist; instead, it relies on general anostracan adaptations – resistant resting eggs, passive dispersal, and physiological flexibility of larvae, juveniles, and adults (Hawes 2009 ). Although its detritivores feeding differs somewhat from the filter-feeding typical of many Branchinecta (Hawes 2008 ), its life-history strategy does not indicate unique Antarctic adaptation (Peck et al. 2006 ). Resting eggs of B. gaini were most likely transported from Chilean freshwater bodies to island groups (Falkland Islands, South Georgia, South Orkney Islands, South Shetland Islands) and directly to Antarctica (e.g., James Ross Island) via passive dispersal vectors. Colonization probably proceeded both from South America and via stepping-stone islands, and movements were not strictly unidirectional (Hawes 2009 ). Subsequent gradual range expansion likely occurred from James Ross Island toward Marguerite Bay, where environmental conditions permitted persistence (Hawes 2008 ), with local population establishment following each successful dispersal event (Hawes 2009 ). The prevailing colonization model posits that B. gaini spread as resting eggs during the last ~ 10,000 years after the Penultimate (Last) Glacial Maximum (20,000–18,000 BP) (Ralph 1967 ). Early evidence included egg microfossils dated to ~ 4200 BP on James Ross Island (Björck et al. 1996 ) and ~ 5500 BP on Signy Island, South Orkney Islands (Jones et al. 2000 ), later extended to ~ 9300 BP on Horseshoe Island, Marguerite Bay (Hodgson et al. 2013 ). More recently, COI molecular-clock analyses and geographic haplotype patterns suggest that B. gaini may have survived the last glacial period in an as-yet unidentified Antarctic refugium (Pokorný et al. 2024 ). Secondly, the species must not only disperse but also survive and establish in new territories. This may be achieved less through specific adaptations to extreme Antarctic conditions than through general biological traits common to anostracans. Below we consider the main factors that can limit or promote the spread of B. gaini : 1) Branchinecta gaini tolerates wide fluctuations in abiotic conditions, with temperature being the most critical. Its physiological flexibility allows it to withstand variations of up to 50°C. Adults survive up to 25°C in summer, while overwintering eggs remain viable down to − 25°C (Peck 2005 ). Adults lack antifreeze proteins, and hemolymph crystallizes at − 5°C (Hawes et al. 2008 ). With ongoing climate warming, habitats are gradually changing, providing longer periods of favorable conditions for growth, feeding, and reproduction. Temperature also influences oxygen availability. Oxygen demand increases with temperature, while under ice cover metabolic rates decline, enabling survival despite hypoxia (Pociecha 2007 ). During March–April 2020, we observed living individuals under ice for up to three weeks in ponds on Uruguay and Irizar Islands. This extended survival may allow later-maturing females to produce more overwintering eggs, increasing both population size and dispersal potential. Salinity is another critical factor. Low concentrations may stimulate development, but seawater intrusions reaching ~ 20 psu are lethal to all stages except eggs (Pociecha & Dumont 2008 ). Even slight increases in salinity strongly limit survival (Hawes et al. 2008 ) because the permeable cuticle leads to osmotic imbalance and desiccation (Ralph 1967 ). 2) Another reason for the success of B. gaini is the near absence of antagonistic interactions in Antarctic freshwaters. As the largest invertebrate present, it is defenseless against predators, yet fish are absent from inland waters (Trokhymets et al. 2022 ) and invertebrate predators are rare (Laybourn-Parry 2002 ). Predation is therefore limited to birds, such as Kelp Gulls ( Larus dominicanus ) and South Polar Skuas ( Stercorarius maccormicki ), which we observed occasionally feeding on B. gaini in ponds and rock pools around the Argentine Islands. Similar predation by waterfowl has been reported previously (Green et al. 2005 ). Interspecific competition is also minimal. Branchinecta gaini overlaps only partly with the copepod B. poppei in diet (small bacteria, large diatoms). Although both species co-occurred in some reservoirs (e.g., Grotto Island), our Chi-squared analysis showed no significant relationship between their presence and abundance. Parasites may also influence populations. The cestode Branchiopodataenia arctowskii uses B. gaini as an intermediate host, with gulls as definitive hosts (Jarecka 1984 ). This parasite is not Antarctic-endemic and also occurs in the Northern Hemisphere (Bondarenko & Kontrymavicius 2004). Although data are lacking for the Wilhelm Archipelago, observed gull and skua predation on B. gaini suggests that parasite transmission may occur locally. 3) Branchinecta gaini can form symbiotic associations with microorganisms. Recent studies describe phylosymbiosis in the microbiomes of anostracans, particularly on gills and in the gut, which may enhance survival in harsh environments (Schwob et al. 2024 ). 4) Branchinecta gaini occurs in reservoirs across a wide range of trophic states. In our study, it was found in oligotrophic (e.g., L1 on Uruguay Island), mesotrophic, and even eutrophic water bodies (e.g., RP18 on Petermann Island). It also inhabits ponds with large amounts of decomposed moss, provided free water space remains above the substrate (e.g., RP14 on Maly Berthelot Island). Mann-Whitney-Wilcoxon tests indicated that B. gaini was significantly more common in deeper waters. While most populations occur in mesotrophic waters, unusual cases of gigantism have been reported in highly eutrophic ponds. On King George Island, specimens reached 28.1 mm (females) and 29.8 mm (males) in a penguin-influenced pond (Jurasz et al. 1983 ), far exceeding the typical 16 mm (Hawes 2009 ). However, hypertrophic conditions appear lethal: during our study no B. gaini were found in guano-rich ponds on Moot Island (Fig. 15 ). 5) Branchinecta gaini has a flexible feeding strategy. It scrapes organic matter from substrates and manipulates detritus with appendages, often swimming belly-up while shredding and consuming particles (Hawes 2008 ). Gut contents include algae, cyanobacterial mats, fungi, protists, rotifers, tardigrades, mites, chironomids, and remains of B. poppei and B. gaini . This confirms it as a detritivore and benthic herbivore, but also capable of cannibalism and opportunistic predation (Paggi 1996 ; Pociecha & Dumont 2008 ). We directly observed both benthic scraping and suspension feeding in P11 on Petermann Island and L1 on Uruguay Island. Transparent water revealed individuals scraping cyanobacterial mats, while others swam belly-up, generating feeding currents and filtering suspended matter. 6) Survival is also supported by a univoltine life cycle, with one generation per year. On King George Island, eggs hatch in November, adults appear in December, and reproduction continues from January until freeze-over in May (Jurasz et al. 1983 ). In the Wilhelm Archipelago, harsher conditions shorten the cycle. Adults did not appear until January, and juveniles were still present in February alongside mature individuals. Reservoirs began freezing in late March 2020, and by early April adults were scarce (L1 on Uruguay Island). Thus, the active phase lasted 4–5 months instead of six. Notably, juveniles dominated in March 2020, suggesting that some eggs may hatch prematurely in the year they are laid when shallow areas freeze – a phenomenon also described by Jurasz et al. ( 1983 ). 7) A critical adaptation is the production of resting eggs capable of cryptobiosis. These double-shelled eggs (Jurasz et al. 1983 ) survive freezing to − 25°C and desiccation (Peck 2004 ). Large egg banks ensure mass hatching and facilitate dispersal (Brendonck 1996 ). After hatching, rapid development produces new egg cohorts, reinforcing the cycle. We observed dense aggregations of adults in small pools drying down (e.g., RP11 on Grotto Island, ponds near Palmer Station). Such conditions likely promote mass oviposition, boosting local egg banks. 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) Anthropogenic impacts are becoming increasingly relevant. Plastic pollution in the Maritime Antarctic alters behaviour and gene expression in B. gaini , suggesting nanoplastics threaten biodiversity (Bergami et al. 2022 ). The species is also sensitive to nanosized titanium dioxide (n-TiO₂), a common pollutant, and has been proposed as a biomonitor (González-Aravena et al. 2022 ). Additionally, it may serve as a bioindicator of oligotrophic ponds (De Los Rios et al. 2008). Third, the species must also possess mechanisms of distribution. In anostracans, two main dispersal strategies are recognized (Jocqué et al. 2010 ): active dispersers, which can move independently into new habitats; passive dispersers, which require external vectors for transport. Branchinecta gaini belongs to the latter group, as it cannot actively move between freshwater bodies via seawater, land, or air. In Antarctica, its dispersal is therefore accidental and occurs through random transport of resting eggs. Such egg-mediated dispersal is common in many anostracans (Brendonck 1996 ). Four passive dispersal vectors are relevant in Antarctic ecosystems (Hawes 2009 ): anthrochory, hydrochory, anemochory, and zoochory. Below, we examine these in the context of B. gaini . 1) Anthrochory refers to dispersal mediated directly or indirectly by humans. Although some authors dismiss this vector for B. gaini (Hawes 2009 ), our observations suggest it is plausible. Tourism in the Wilhelm Archipelago has increased in recent decades, with Petermann Island serving as a major landing point for thousands of visitors annually. At least one nearby pond (RP18) hosts B. gaini . Tourists walking through such ponds could pick up sediment containing eggs on their boots, especially when mixed with penguin guano. If sediment remains sticky, eggs may not be removed while walking on snow. During boot cleaning before re-embarkation, eggs could then be washed into another water body. Thus, eggs may be transferred between ponds on the same island. Further transfer between islands is less likely, but possible. For instance, tourists sometimes move directly between Petermann and Great Yalour Islands without ship-based decontamination. Mud with eggs could fall off boots onto snow, meltwater then carrying eggs into ponds. Yacht-based tourism increases the risk of introducing eggs to smaller surrounding islands. The same risk applies to inexperienced researchers who may not thoroughly wash their boots. Therefore, we argue that anthrochory could be an important dispersal vector, though this hypothesis requires experimental confirmation. 2) Hydrochory is dispersal by water. Branchinecta gaini eggs may spread stochastically within islands but usually over short distances. Most reservoirs in this region are isolated, located in rock crevices or terraces. However, cascades of interconnected ponds do occur on Irizar, Eight, and Maly Berthelot Islands. During snow and ice melt, water may flow between reservoirs, carrying buoyant eggs to downstream habitats (Brendonck & Riddoch 1999 ). Thus, hydrochory enables local dispersal but rarely long-distance spread. 3) Anemochory is dispersal by wind. Dried sediments containing eggs can be blown short distances between nearby rock pools (Brendonck & Riddoch 1999 ). Long-distance aerial dispersal is considered unlikely (Vanschoenwinkel et al. 2008 ). This mechanism would be restricted to shallow pools that dry completely during summer, leaving exposed egg-containing sediments vulnerable to wind transport. For example, this may occur between reservoirs on Maly Berthelot Island. 4) Zoochory is dispersal mediated by animals, particularly birds, and is likely the most important vector for B. gaini . Birds frequently congregate around freshwater ponds for drinking, bathing, feeding, and resting (Viana et al. 2013 ). In the Wilhelm Archipelago, potential vectors include the Kelp Gull, South Polar Skua, Antarctic Tern ( Sterna vittata ), and Snowy Sheathbill ( Chionis albus ). We observed Kelp Gulls and South Polar Skuas actively feeding on B. gaini . Other studies also report predation by terns and skuas (Nedbalová et al. 2017 ). Zoochory occurs in two main forms: epizoochory and endozoochory (Hawes 2009 ). Epizoochory involves external attachment of eggs. Branchinecta gaini eggs can adhere to bird feet and feathers together with mud when birds bathe or feed. Such transport is known in other crustaceans (Trokhymets et al. 2024 ) and may occur both within and between islands. This mechanism is plausible given the abundance of nesting birds throughout the Wilhelm Archipelago. For instance, we observed South Polar Skuas flying ~ 13 km between Locator and Galindez Islands, distances sufficient for egg transport. Endozoochory involves ingestion of eggs, which survive passage through the digestive tract. Eggs may be swallowed incidentally with water or via predation on gravid females. After defecation, viable eggs can hatch in new habitats (Green & Figuerola 2005 ; Rogers 2014 ). In other regions, egg transport has been demonstrated by insects (Beladjal & Mertens 2009 ), fish (Beladjal et al. 2007 ), amphibians (Bohonak & Whiteman 1999 ), and birds (Green et al. 2005 ). In Antarctica, only birds are relevant, as other potential predators are absent. Thus, gulls, skuas, and terns are the most likely long-distance dispersal agents. In summary, B. gaini occurs in freshwater bodies with cyanobacterial mats and detritus-rich bottoms. Its dispersal appears to depend on the presence of birds for zoochory and on water connections for hydrochory, but it is generally absent in ponds heavily influenced by penguin colonies. Within the Wilhelm Archipelago, the broad range of dispersal vectors supports colonization, with zoochory and hydrochory emerging as the most effective mechanisms. 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, ID, KJ, AZ, and PDLRE 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. Conflict of interest and ethics approval. All 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. Data availability. All data are presented in the main manuscript and supplementary table (related file). References Bauer DF (1972) Constructing confidence sets using rank statistics. JASA 67:687–690. https://doi.org/10.1080/01621459.1972.10481279 Beladjal L, Mertens J (2009) Diaspore dispersal of Anostraca by flying insects. 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1","display":"","copyAsset":false,"role":"figure","size":444712,"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":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/531b4540338be68573710e69.png"},{"id":96314784,"identity":"f49e9295-a97b-43c3-a49f-9a63204e2584","added_by":"auto","created_at":"2025-11-19 17:18:17","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":609229,"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":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/bb128dc3d8dd083711d81c05.png"},{"id":96366238,"identity":"f8999d07-83fd-4951-a09e-ab557aea344d","added_by":"auto","created_at":"2025-11-20 10:11:18","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":854083,"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 – 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hydrobionts and 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":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/43c9ac57604bf71a37b9ea9b.png"},{"id":96314787,"identity":"94aa9991-4250-4777-a6af-650329fa5fff","added_by":"auto","created_at":"2025-11-19 17:18:17","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1731041,"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 (* – Base station №3 for long-term monitoring of \u003cem\u003eB. gaini\u003c/em\u003e), 2 – Rock pool 19; ** – Base station №3 for long-term monitoring of \u003cem\u003eBoeckella poppei\u003c/em\u003e\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/12fa3816421cc8f948051d7b.png"},{"id":96314795,"identity":"2f8fc8fd-7915-4fd2-8edb-e2e783f72d06","added_by":"auto","created_at":"2025-11-19 17:18:17","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":4351936,"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\u003erepresentatives, \u003cstrong\u003ec\u003c/strong\u003e – photo of the Lake 2; 1 – Rock pool 1; * – “Basic freshwater hydrobiological station №2”\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/57a0e0e0c7fad9ecb8df4c49.png"},{"id":96365682,"identity":"7371bc87-08bd-4482-b710-5293f60e93eb","added_by":"auto","created_at":"2025-11-20 10:10:40","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":2055111,"visible":true,"origin":"","legend":"\u003cp\u003eMitina Island and its freshwater body with the registration of \u003cem\u003eBranchinecta gaini\u003c/em\u003e. \u003cstrong\u003ea\u003c/strong\u003e – topographic map of The Barchans, \u003cstrong\u003eb\u003c/strong\u003e – photo of the Pond 3; 1 – Pond 3\u003c/p\u003e","description":"","filename":"image7.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/9f988d6fed485e4ad08169ba.png"},{"id":96314800,"identity":"541c8775-cee5-45b2-9f4b-390642d0185e","added_by":"auto","created_at":"2025-11-19 17:18:17","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":5491890,"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":"image8.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/e17bc437ed14e311c1ee2deb.png"},{"id":96364929,"identity":"28a6c85e-1d55-46f0-a1a0-2f1bb1771874","added_by":"auto","created_at":"2025-11-20 10:09:48","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":4311653,"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\u003ed\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":"image9.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/68b71acac8ff9b71ff9ef401.png"},{"id":96365936,"identity":"74f9afbc-f1da-4e62-8b98-e78f179432a4","added_by":"auto","created_at":"2025-11-20 10:10:58","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":1733476,"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":"image10.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/f38d388dc861ced1a434fcc4.png"},{"id":96365950,"identity":"9e0b35d4-8f16-4595-ac26-957e775489e8","added_by":"auto","created_at":"2025-11-20 10:10:59","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":2589511,"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 (* – Base station №1 for long-term monitoring of \u003cem\u003eB. gaini\u003c/em\u003eand \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":"image11.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/c07aa63b377a9cb03d2015d9.png"},{"id":96364539,"identity":"4bccd2e7-395a-4676-8df8-ad3be8010690","added_by":"auto","created_at":"2025-11-20 10:09:23","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":2164196,"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":"image12.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/c6eb8296db4f42e663e73688.png"},{"id":96365792,"identity":"44e70e60-0c4f-4f4c-933f-e22f66d030a3","added_by":"auto","created_at":"2025-11-20 10:10:47","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":4420157,"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":"image13.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/82dce6027f589492ef4fe2cd.png"},{"id":96365785,"identity":"f9407530-75b1-4c2e-a871-b5467f41f319","added_by":"auto","created_at":"2025-11-20 10:10:47","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":989611,"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":"image14.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/072ddd00338240c70819a850.png"},{"id":96314801,"identity":"dfc8387f-9edb-433f-92fe-95c45dd7be7e","added_by":"auto","created_at":"2025-11-19 17:18:17","extension":"png","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":3756744,"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 freshwater bodies near the penguin colony; 1 – large polluted pond, around which other polluted freshwater bodies are located\u003c/p\u003e","description":"","filename":"image15.png","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/138c521dc7683fdabcf82b1d.png"},{"id":96369352,"identity":"7a21f312-ed4d-49cc-a280-0f62b5ac9ce1","added_by":"auto","created_at":"2025-11-20 10:20:37","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":39921713,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7830481/v1/f8dc811e-3a6f-414c-8cde-bf0d34ebef51.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Distribution 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 living organisms, particularly in terrestrial ecosystems (Convey \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Unlike the relatively stable marine environment, terrestrial habitats experience strong daily and seasonal fluctuations in environmental variables such as temperature. As a result, terrestrial biota must show high physiological and ecological flexibility to survive (Peck \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). There is general consensus that most species inhabiting Antarctica are long-term endemic lineages that have adapted to these harsh conditions over millions of years. However, current rapid warming is altering these ecosystems, potentially expanding species\u0026rsquo; ranges, increasing population sizes and productivity, reshaping community structure, and allowing the introduction of non-native species (Convey and Peck \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Freshwater reservoirs \u0026ndash; both permanent and temporary (lakes, ponds, and rock pools) \u0026ndash; play a special role in Antarctic terrestrial ecosystems. Among these, small water bodies are the most common, with rock pools predominating (Hawes et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). These pools represent some of the oldest and most extreme temporary habitats (Brendonck and Riddoch \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1999\u003c/span\u003e). Worldwide freshwater rock pools host about 460 animal species. Antarctic rock pools are remarkable for their exceptionally high faunal diversity: they contain 42 genera of active dispersers and 41 genera of passive dispersers (Jocqu\u0026eacute; et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). By comparison, North American rock pools support only 32 and 14 genera with the same dispersal strategies, respectively (Jocqu\u0026eacute; et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2010\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIn Antarctic freshwater ecosystems, biodiversity and biomass are primarily supported by cyanobacteria and plants, while animals contribute to ecosystem stability. Among animals, benthic and planktonic forms dominate across taxonomic groups (Gibson et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Altogether, 336 invertebrate taxa (species, genera, and higher-level groups) have been recorded in Antarctic freshwater bodies, with 121 known from Maritime Antarctica (Dartnall \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Crustaceans account for 66 taxa, nine of which occur in the Maritime Antarctic. On the Antarctic Peninsula, only four freshwater crustacean species have been reported: two branchiopods and two copepods (Diaz et al. 2019; Trokhymets et al. \u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe class Branchiopoda Latreille, 1817 currently includes about 500 species. Anostracans, one of its major groups, occur mainly in temporary freshwater habitats, although some species inhabit saline waters. Most anostracans are omnivorous filter feeders, though predatory species are also known (Brendonck et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). They withstand unfavourable conditions by producing resting egg (\u0026ldquo;cyst\u0026rdquo;) banks (Brendonck \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1996\u003c/span\u003e). Anostracans are relatively large branchiopods, and many new species have been described in recent decades (Rogers and Ferreira \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). Their known diversity has increased from 258 species in 1993 (Belk and Brtek \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1995\u003c/span\u003e) to about 300 species in 2008 (Brendonck et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2008\u003c/span\u003e), a growth partly explained by the fact that nearly 25% of species are known only from their type localities (Belk and Brtek \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1995\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe genus \u003cem\u003eBranchinecta\u003c/em\u003e Verrill, 1869 (family Branchinectidae Daday, 1910) is the only group of anostracans occurring in Antarctic freshwater bodies. It currently includes about 48 species, distributed across most continents except Australia (Rogers et al. \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2020b\u003c/span\u003e; Beladjal and Mounia \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Evtimova et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe Antarctic fairy shrimp, \u003cem\u003eBranchinecta gaini\u003c/em\u003e Daday, 1910, is the sole anostracan species recorded in Antarctic freshwater habitats (Rosenfeld et al. \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). It was first discovered on Petermann Island (65\u0026deg;10\u0026prime;34\u0026Prime;S, 66\u0026deg;32\u0026prime;30\u0026Prime;W) and nearby small islands of the Wilhelm Archipelago during the Second French Antarctic Expedition, led by Jean-Baptiste Charcot, when Mr. L. Hein collected specimens in 1909 (Daday de De\u0026eacute;s 1910). For many years, \u003cem\u003eB. gaini\u003c/em\u003e was thought to be widespread, with records from southern South America (De Los R\u0026iacute;os et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Rogers et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; De Los R\u0026iacute;os-Escalante and Kotov \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), the Falkland Islands (Weller \u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e1975\u003c/span\u003e; Hawes \u003cspan citationid=\"CR35\" 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, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), the 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), the South Shetland Islands (Janiec \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Toro et al. \u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Rochera and Camacho \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), and the Antarctic Peninsula (Bj\u0026ouml;rck et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Nedbalov\u0026aacute; et al. \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Maturana et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). According to this interpretation, \u003cem\u003eB. gaini\u003c/em\u003e coexisted in Patagonia with the morphologically similar \u003cem\u003eBranchinecta granulosa\u003c/em\u003e Daday, 1902 (Linder \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e1941\u003c/span\u003e; Rogers et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Several reports even listed \u003cem\u003eB. granulosa\u003c/em\u003e from Antarctica (Bryant \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1945\u003c/span\u003e; Polishuk et al. \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2009\u003c/span\u003e), but most authors rejected these as misidentifications of \u003cem\u003eB. gaini\u003c/em\u003e (Pugh et al. \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Rogers et al. \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2020a\u003c/span\u003e). The presence of \u003cem\u003eB. gaini\u003c/em\u003e in South America and the Falkland Islands has likewise been questioned (Pugh et al. \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Rogers et al. \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2020a\u003c/span\u003e). Subsequently, Rogers et al. (\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2020b\u003c/span\u003e) argued that all Patagonian records of \u003cem\u003eB. gaini\u003c/em\u003e in fact 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 and phylogenetic analyses published in 2024 further revealed minimal genetic differentiation between the two species, raising the possibility that they represent a single taxon with slight morphological variation among populations (Pokorn\u0026yacute; et al. \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Thus, two main interpretations exist: (1) \u003cem\u003eB. granulosa\u003c/em\u003e and \u003cem\u003eB. gaini\u003c/em\u003e are separate species, restricted to South America and Antarctica (plus adjacent islands), respectively, with Falkland Island populations requiring further study; or (2) \u003cem\u003eB. granulosa\u003c/em\u003e and \u003cem\u003eB. gaini\u003c/em\u003e are conspecific. In this publication, we adopt the more widely accepted first view (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) but emphasize the need for further research. If \u003cem\u003eB. gaini\u003c/em\u003e proves invalid, all Antarctic and sub-Antarctic records would need to be reclassified as populations of \u003cem\u003eB. granulosa\u003c/em\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eResearch on \u003cem\u003eB. gaini\u003c/em\u003e in the Wilhelm Archipelago has remained fragmentary since its first discovery by L. Hein in 1909 (Daday de De\u0026eacute;s 1910). Most records come from scattered references by English and Ukrainian researchers, unpublished reports, and a few publications (Polishuk et al. \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Chernov et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). In these accounts, the species was often identified as \u003cem\u003eB. granulosa\u003c/em\u003e, with findings reported from several islands (Galindez, Skua, Mitina, and Uruguay), usually without precise coordinates or descriptions of the freshwater bodies. Subsequent revisions reassigned these records to \u003cem\u003eB. gaini\u003c/em\u003e (Chernov et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Trokhymets and Dykyy \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, detailed data on its local distribution within the Wilhelm Archipelago are still lacking. The aim of this study is therefore to provide a comprehensive assessment of the occurrence and distribution of \u003cem\u003eB. gaini\u003c/em\u003e in the Wilhelm Archipelago, based on new field records and analyses.\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 from freshwater bodies in the Wilhelm Archipelago region. We followed the classification of freshwater bodies proposed by Trokhymets et al. (\u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2024\u003c/span\u003e): Lakes \u0026ndash; do not freeze to the bottom, depth\u0026thinsp;\u0026gt;\u0026thinsp;2 m, surface area\u0026thinsp;\u0026ge;\u0026thinsp;100 m\u0026sup2;; Ponds \u0026ndash; freeze to the bottom in winter, depth\u0026thinsp;\u0026lt;\u0026thinsp;2 m, surface area 10\u0026ndash;100 m\u0026sup2; (or larger, but shallow); Rock pools \u0026ndash; freeze to the bottom in winter, depth\u0026thinsp;\u0026le;\u0026thinsp;1 m, surface area\u0026thinsp;\u0026lt;\u0026thinsp;10 m\u0026sup2;.\u003c/p\u003e\u003cp\u003eSamples were collected during several Ukrainian Antarctic Expeditions: 12th Expedition (March 2007) \u0026ndash; 8 samples from freshwater bodies of four islands and Cape Rasmussen, 12th Expedition (January\u0026ndash;February 2008) \u0026ndash; 7 samples from six islands, 14th Expedition (January\u0026ndash;March 2010) \u0026ndash; 18 samples from 12 islands and Cape Rasmussen, 25th Expedition (February\u0026ndash;April 2020) \u0026ndash; 111 samples from 20 islands and three continental capes.\u003c/p\u003e\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e lists freshwater bodies where \u003cem\u003eB. gaini\u003c/em\u003e was recorded, with GPS coordinates; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e lists those where it 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\u003eRP, 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\u003eRP, 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\u003eRP\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\u003eRP\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\u003eRP\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\u003eRP, 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\u003eRP, 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 taken using a 2-liter water sampler. Volumes of 5\u0026ndash;20 L were filtered through a 100 \u0026micro;m conical plankton net (Janiec \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e1991\u003c/span\u003e; Burian and Trokhymets \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). If fairy shrimp were visible but not captured in the plankton samples (due to low abundance), they were collected directly with a hand net (Jo et al. \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). This approach allows quantitative assessment of copepods, but only qualitative (presence/absence) assessment of fairy shrimp, as their behaviour and patchy distribution make quantitative sampling unreliable (Pociecha and Dumont \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eSpecimens were preserved in 99% ethanol for molecular analyses (Pokorn\u0026yacute; et al. \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) and in 4% formaldehyde for morphological study (Pociecha and Dumont \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Salinity was measured with a salinity meter, and water temperature with a mercury thermometer.\u003c/p\u003e\n\u003ch3\u003eTaxonomic identification\u003c/h3\u003e\n\u003cp\u003eSamples from 2007\u0026ndash;2010 were analyzed in the laboratory of the Educational and Scientific Center \u0026ldquo;Institute of Biology and Medicine\u0026rdquo;, Taras Shevchenko National University of Kyiv. Samples from 2020 were studied at the Ukrainian Antarctic Akademik Vernadsky Station. Morphological examinations were carried out with an MBS-12 stereomicroscope. Adult \u003cem\u003eB. gaini\u003c/em\u003e were identified based on structural characters of the second antenna, gonopodia, and male genital segments (Daday de De\u0026eacute;s 1910; Jurasz et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1983\u003c/span\u003e; Rogers et al. \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2020a\u003c/span\u003e). Larvae were identified using published illustrations of the life cycle (Jurasz et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1983\u003c/span\u003e). Different developmental stages of \u003cem\u003eB. gaini\u003c/em\u003e are shown 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=\"CR28\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) and UK Polar Data Centre VERSION 7.3 (Version 1.0) by Gerrish (\u003cspan citationid=\"CR27\" 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\u003eNormality of data was tested with the Shapiro\u0026ndash;Wilk test, which indicated non-normal distributions. Therefore, the nonparametric Mann\u0026ndash;Whitney\u0026ndash;Wilcoxon test (Bauer \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1972\u003c/span\u003e) was applied to assess the effect of depth, salinity, and temperature on the presence of \u003cem\u003eB. gaini\u003c/em\u003e. Pearson\u0026rsquo;s chi-squared test (Pearson \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e1900\u003c/span\u003e) was used to evaluate the influence of cyanobacterial mats, presence of \u003cem\u003eBoeckella poppei\u003c/em\u003e (Mr\u0026aacute;zek, 1901; Copepoda, Calanoida), and sampling time (month, year) on the presence of \u003cem\u003eB. gaini\u003c/em\u003e.\u003c/p\u003e\u003cp\u003eAnalyses included only freshwater bodies located on islands where \u003cem\u003eB. gaini\u003c/em\u003e has previously been recorded (either in earlier studies or in the present work). Although suitable habitats exist on other islands, there is currently no evidence of colonization, and including them would bias the results. All analyses were performed in RStudio v1.4.1106 with R v4.0.5.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cem\u003eBranchinecta gaini\u003c/em\u003e was recorded in two freshwater bodies on Uruguay and Galindez Islands (out of four islands and Cape Rasmussen examined) in 2007; in three reservoirs on three islands (out of six examined) in 2008; in six freshwater bodies on six islands (out of 12 examined) and Cape Rasmussen in 2010; and in 27 reservoirs on nine islands (out of 20 examined) and three continental capes in 2020 (Tables\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Some sites, such as Galindez Island, were sampled repeatedly in different years, so the total number of islands with \u003cem\u003eB. gaini\u003c/em\u003e records is not a simple sum across years. In total, \u003cem\u003eB. gaini\u003c/em\u003e was found in 32 freshwater bodies on 12 islands of the Wilhelm Archipelago (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Eleven of these islands yielded records of the species for the first time. Below, we describe in detail the reservoirs and islands where \u003cem\u003eB. gaini\u003c/em\u003e was recorded.\u003c/p\u003e\u003cp\u003e\u003cb\u003e1. Uruguay Island\u003c/b\u003e belongs to the Argentine Islands group of the Wilhelm Archipelago (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003ea). It lies in the Bellingshausen Sea, 2 km northeast of Galindez Island and about 6 km from the coast of the Kyiv Peninsula. The island consists of northern and southern parts connected by a narrow isthmus.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe pond P1 is located in the southern part of the island, on the left side of the central rocky ridge when moving from south to north (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003eb). It lies at an altitude of 15 m a.s.l., measures about 50 \u0026times; 20 m, and reaches a depth of 1.5 m. The bottom is rocky, with patches of brown cyanobacterial mat on the walls. One adult \u003cem\u003eB. gaini\u003c/em\u003e was recorded in March 2007. A resample in April 2020 yielded no individuals, likely because the pond was covered with a 5 cm layer of ice at the time; a hole had to be drilled to collect the sample. It is probable that adults had already died after laying overwintering eggs.\u003c/p\u003e\u003cp\u003eThe pond P9 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), at an altitude of 11 m a.s.l. It measures approximately 120 \u0026times; 50 m and is up to 0.7 m deep. The bottom is rocky and the walls bear patches of brown cyanobacterial mat. Several adult \u003cem\u003eB. gaini\u003c/em\u003e were recorded beneath a thin ice cover in April 2020.\u003c/p\u003e\u003cp\u003eThe lake L1, the elongated depression, is located in the centre of the northern part of the island (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003ed\u0026ndash;e). It is situated at 40 m a.s.l., measuring about 300 \u0026times; 80 m with a maximum depth of 8 m in its northern part. L1 is the largest lake in the Argentine Islands. Its stony bottom is partly covered with green organic matter, and the walls with a thin cyanobacterial mat. It is one of the few reservoirs in the region that does not freeze to the bottom in winter, allowing aquatic fauna to remain active throughout the coldest season.\u003c/p\u003e\u003cp\u003eL1 is hydrologically connected by channels to a subglacial lake beneath a 12 m thick ice dome, with a depth of 9 m. During thermal drilling of the ice dome, fragments of \u003cem\u003eB. gaini\u003c/em\u003e limbs were found (Chernov et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), confirming the connection. However, as \u003cem\u003eB. gaini\u003c/em\u003e is not a troglobiont, its survival in a closed subglacial ecosystem is highly unlikely. L1 therefore represents a unique ecosystem where typical Antarctic freshwater organisms may coexist with species occasionally transferred from the subglacial environment.\u003c/p\u003e\u003cp\u003ePreviously, L1 was proposed as Base Station №2 for continuous monitoring of \u003cem\u003eB. poppei\u003c/em\u003e (Trokhymets et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). We further propose that L1 should serve as \u0026ldquo;Basic Freshwater Hydrobiological Station №1\u0026rdquo; for permanent monitoring of hydrobionts, and also as Base Station №2 for long-term monitoring of \u003cem\u003eB. gaini\u003c/em\u003e and \u003cem\u003eB. poppei\u003c/em\u003e in this part of the Wilhelm Archipelago (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\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\u003cem\u003eBranchinecta gaini\u003c/em\u003e was recorded in L1 in February 2010 and March 2020. In 2010, 19 individuals were collected (nine females, four males, and six juveniles). In 2020, 13 individuals were collected (three females and 10 juveniles). Weekly monitoring from March 10 to April 14, 2020, showed that \u003cem\u003eB. gaini\u003c/em\u003e was consistently present, although numbers declined; the final sample (April 14) contained three live individuals (one female, two males) and one dead specimen.\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\u003eThe pond P2 lies near the island\u0026rsquo;s highest point (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e5\u003c/span\u003eb\u0026ndash;c). Although morphologically similar to a rock pool, it is classified here as a pond. It has a roughly circular shape, measuring about 4 \u0026times; 4 m with a depth of up to 30 cm. The walls are coated with a 1 mm thick brown cyanobacterial mat. \u003cem\u003eBranchinecta gaini\u003c/em\u003e was consistently recorded in P2 during all four years of study: March 2007 (12 adults), February 2008 (10 adults), January 2010 (9 adults), and February 2020 (15 adults). This is the only freshwater body where the species was detected in every sampling year. We therefore propose P2 as Base Station №3 for long-term monitoring of \u003cem\u003eB. gaini\u003c/em\u003e population dynamics. Additionally, we suggest relocating Base Station №3 for monitoring of \u003cem\u003eB. poppei\u003c/em\u003e from Grotto Island (Trokhymets et al. \u003cspan citationid=\"CR74\" 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 identified (Nabokin et al. \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe rock pool RP19 lies on the top of a flat hill. It measures 3 \u0026times; 3 m with a depth of up to 0.3 m. The bottom is rocky and covered with organic matter, while the walls bear a brown cyanobacterial mat. At the time of sampling, the water was opaque due to a phytoplankton bloom. In March 2020, 23 sexually mature \u003cem\u003eB. gaini\u003c/em\u003e were recorded.\u003c/p\u003e\u003cp\u003e\u003cb\u003e3. Skua Island\u003c/b\u003e belongs to the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e6\u003c/span\u003ea). It is located in the Bellingshausen Sea, 0.7 km southwest of the Ukrainian Antarctic Akademik Vernadsky Station on Galindez Island and about 6 km from the coast of the Kyiv Peninsula.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe rock pool RP1 lies on a slope terrace along the southwest coast of the island. It has an elongated polygonal shape, measuring 2 \u0026times; 1 m with a depth of 0.3 m. The stone bottom is partly covered with green-brown organic matter, while the walls are overgrown with a 1 mm thick brown cyanobacterial mat (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e6\u003c/span\u003eb). Seven sexually mature \u003cem\u003eB. gaini\u003c/em\u003e were recorded here in February 2008.\u003c/p\u003e\u003cp\u003eThe Lake 2 (L2) is one of the largest freshwater bodies in the Wilhelm Archipelago is also located on Skua Island (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e6\u003c/span\u003ec). It lies in the northern part of the island, near the ice dome and several stone hills (65\u0026deg;15\u0026prime;10\u0026Prime;S, 64\u0026deg;15\u0026prime;40\u0026Prime;W). For much of the year, the reservoir remains ice-covered, making its full extent difficult to determine. However, during maximum thawing in February\u0026ndash;March 2020, its approximate size was estimated at 200 \u0026times; 85 m, with a depth exceeding 2 m. Based on these dimensions, it is classified as a lake.\u003c/p\u003e\u003cp\u003eNo crustaceans were detected by visual inspection in 2020, and detailed analysis of the aquatic fauna was not possible at that time. Future studies will be needed to assess colonization processes in this reservoir. Its proximity to Galindez Island makes it particularly convenient for long-term ecological monitoring. We therefore propose this lake as Basic Freshwater Hydrobiological Station №2 for permanent 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, currently unnamed) is part of the Barchans subgroup of the Argentine Islands (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e7\u003c/span\u003ea). It is the northeastern island of the Barchans, situated in the Bellingshausen Sea, 2 km west of Galindez Island and about 8.5 km from the continental coast of the Kyiv Peninsula.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe pond P3 is located on a stone plateau along the northwestern coast of the island, at an elevation of 12 m a.s.l. (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e7\u003c/span\u003eb). It has an irregular quadrangular shape with unequal sides, measuring 4 \u0026times; 3 m and up to 0.3 m deep. The stony bottom contains accumulations of semi-decomposed moss in the deepest part, and the walls and bottom are coated with a thin brown cyanobacterial mat. \u003cem\u003eBranchinecta gaini\u003c/em\u003e was recorded here in February 2008 (14 sexually mature individuals), February 2010 (7 individuals), and February 2020 (24 individuals).\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\u003eThe pond P4 lies in the northern part of the island, at the base of a narrow peninsula extending northeastward. It was formed on a stone terrace near a hill, with scattered stone blocks shaping it into a polygonal depression (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e8\u003c/span\u003eb\u0026ndash;c). The pond covers an area of about 12 m\u0026sup2; and has a depth of 0.4 m. Its bottom contains an accumulated layer of semi-decomposed moss, while the walls are coated with a cyanobacterial mat. Three sexually mature \u003cem\u003eB. gaini\u003c/em\u003e were recorded here 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\u003eThe pond P5 is situated on the northeastern part of the island at an elevation of 7 m a.s.l. (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003eb). It occupies a stone gorge and has an L-shaped outline, measuring 7 \u0026times; 2 m with a depth of 0.4 m. The rocky walls are covered with a thick brownish-red cyanobacterial mat (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003ec), and the bottom contains a small amount of silt from decomposed moss. Twenty sexually mature \u003cem\u003eB. gaini\u003c/em\u003e were recorded here in March 2010.\u003c/p\u003e\u003cp\u003eThe rock pool RP18 is located in the southern coastal part of the island at 8 m a.s.l. (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003ed). It has an irregular shape resembling a cross, with dimensions of 3 \u0026times; 2 m and a depth of 0.3 m. It lies in a hollow on a slope between large stone blocks. The walls are coated with a thin brown cyanobacterial mat, while the bottom holds several centimetres of silt and partially decomposed moss. Fifteen adult \u003cem\u003eB. gaini\u003c/em\u003e were recorded here in February 2020.\u003c/p\u003e\u003cp\u003eThis reservoir is unique in our study as it appears to be strongly influenced by local avifauna. Small colonies of Gentoo penguins (\u003cem\u003ePygoscelis papua\u003c/em\u003e) are situated just tens of meters above and below RP18. As a result, feathers and guano enter the pond with meltwater, making the water opaque and leaving feathers floating on the surface. RP18 is less polluted than reservoirs located directly within the penguin colony, where crustaceans have never been found.\u003c/p\u003e\u003cp\u003eThe pond P11, rhomboid in shape, lies in the northern part of the island at an elevation of 16 m a.s.l. (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003ee). It occupies a stone hollow, measuring 5 \u0026times; 3 m with a depth of up to 0.4 m. The walls are coated with a thin brown cyanobacterial mat to a depth of 30 cm, and the bottom contains some silt from decomposed moss. During visual inspection in February 2020, numerous anostracans were observed grazing on the cyanobacterial mats covering the stones. In the sample, 62 individuals were recorded (56 adults, one juvenile, and five larvae).\u003c/p\u003e\u003cp\u003e\u003cb\u003e7. Winter Island\u003c/b\u003e is part of the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e10\u003c/span\u003ea). It lies in the Bellingshausen Sea, only 0.15 km from the Ukrainian Antarctic Akademik Vernadsky Station on neighboring Galindez Island and about 6.5 km from the continental coast of the Kyiv Peninsula.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe rock pool RP2 has an oval shape and is located near the coast, opposite Skua Island (Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e10\u003c/span\u003eb). It occupies a hollow between stone blocks, measuring 3 \u0026times; 2 m with a depth of 0.4 m. The walls are coated with a thin brown cyanobacterial mat, while the gravel bottom holds a 5 cm layer of decomposed and semi-decomposed moss. Three adult \u003cem\u003eB. gaini\u003c/em\u003e were recorded here in February 2010.\u003c/p\u003e\u003cp\u003e\u003cb\u003e8. Irizar Island\u003c/b\u003e belongs to the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e11\u003c/span\u003ea). It lies in the Bellingshausen Sea, 3.5 km northeast of Galindez Island and about 6 km from the continental coast of the Kyiv Peninsula.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe pond P6, elongated polygonal, is located on a terrace along the northernmost rocky ridge of the island, at 15 m a.s.l. (Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e11\u003c/span\u003eb). It measures 6 \u0026times; 2 m with a depth of 0.5 m. The stone walls are coated with a thin brown cyanobacterial mat, and the bottom contains a 0.1 m layer of decomposed and semi-decomposed moss silt. Seven sexually mature \u003cem\u003eB. gaini\u003c/em\u003e were recorded here in February 2020. P6 was designated 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=\"CR74\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe rock pool RP3 lies near the shore, slightly east of P6, in a terrace depression at 12 m a.s.l. It has a triangular shape, measuring 1.5 \u0026times; 0.5 m with a depth of 0.3 m. The stone walls and bottom are coated with a thin cyanobacterial mat. Two adult \u003cem\u003eB. gaini\u003c/em\u003e were recorded in February 2020.\u003c/p\u003e\u003cp\u003eThe rock pools RP4 and RP5 are located north of P6 (Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e11\u003c/span\u003ec). RP4 is spindle-shaped, situated on a rock terrace at 14 m a.s.l., measuring 2 \u0026times; 1 m with a depth of 0.3 m. RP5 lies a few meters higher (15 m a.s.l.) and has a quadrangular shape, measuring 2 \u0026times; 1.5 m with a depth of 0.4 m. Both ponds have walls coated with a thin brown cyanobacterial mat, and their bottoms contain a thin layer of decomposed moss. Five and six sexually mature \u003cem\u003eB. gaini\u003c/em\u003e were found in RP4 and RP5, respectively, in February 2020.\u003c/p\u003e\u003cp\u003eThe pond P7 occupies a terrace on the rock slope at 12 m a.s.l., northwest of the other reservoirs. It has an irregular quadrangular outline, measuring 10 \u0026times; 3 m with a depth of 1 m. The stone walls are covered with a thin brown cyanobacterial mat, while the bottom is free of silt. One adult \u003cem\u003eB. gaini\u003c/em\u003e was recorded here in March 2020.\u003c/p\u003e\u003cp\u003eThe pond P8, round in shape, lies on a terrace of one of the island\u0026rsquo;s hills, at 21 m a.s.l. (Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e11\u003c/span\u003ed). It measures 20 \u0026times; 20 m with a depth of 1 m. The walls are coated with a thin brown cyanobacterial mat extending 30 cm deep, while the stony bottom contains a thin layer of silt from decomposed moss. Seven \u003cem\u003eB. gaini\u003c/em\u003e larvae and juveniles were detected in February 2020. This was the only freshwater body on the island where early developmental stages were observed; no adults were present.\u003c/p\u003e\u003cp\u003eThe rock pool RP6 lies in a depression on a rock slope at 8 m a.s.l. It measures 2 \u0026times; 1.5 m with a depth of 0.3 m. The walls are coated with a thin brown cyanobacterial mat, and the stony bottom has patches of decomposed moss. At the time of sampling, the reservoir was already covered by 3 cm of ice. Three adult \u003cem\u003eB. gaini\u003c/em\u003e were recorded in March 2020.\u003c/p\u003e\u003cp\u003e\u003cb\u003e9. Eight Island\u003c/b\u003e (unofficial name, an officially unnamed) is part of the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e12\u003c/span\u003ea). It lies in the Bellingshausen Sea, 3 km northeast of Galindez Island and about 6 km from the continental coast of the Kyiv Peninsula. The island consists of northern and southern parts connected by an isthmus. Samples were collected in the southern part.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe rock pool RP7 is located on a terrace of the northern slope, at 8 m a.s.l. (Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e12\u003c/span\u003eb). It has a triangular shape, with its base lying under ice and its sharp corner pointing downslope. It measures 3 \u0026times; 2 m and is up to 0.3 m deep. The stone walls are coated with a thin cyanobacterial mat, and the bottom contains silt from semi-decomposed moss. Excess water flows downslope, forming a cascade of small rock pools where crustaceans were also present. As this represents a single connected system, these rock pools were not considered separate reservoirs. Five sexually mature \u003cem\u003eB. gaini\u003c/em\u003e were recorded in RP7 in February 2020.\u003c/p\u003e\u003cp\u003eIn the same area, several smaller, isolated rock pools were found, three of which (the rock pools RP8\u0026ndash;10) contained \u003cem\u003eB. gaini\u003c/em\u003e. These reservoirs have rounded or polygonal shapes, measuring 2\u0026ndash;1 \u0026times; 1\u0026ndash;0.5 m with depths of 0.2\u0026ndash;0.3 m (Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e12\u003c/span\u003ec). Their walls and bottoms are covered with cyanobacterial mats. In February 2020, several adults of \u003cem\u003eB. gaini\u003c/em\u003e were recorded: three in RP8, two in RP9, and two in RP10.\u003c/p\u003e\u003cp\u003e\u003cb\u003e10. Grotto Island\u003c/b\u003e is part of the Argentine Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e13\u003c/span\u003ea). It lies in the Bellingshausen Sea, 0.4 km north of Galindez Island and about 7 km from the continental coast of the Kyiv Peninsula.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe rock pool RP11 is elongated and located on the northwest coast of the island, 20 m from the shore, at 5 m a.s.l. It measures 10 \u0026times; 1 m with a depth of 0.4 m and lies 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 2 mm thick brown cyanobacterial mat, with patches of silt from decomposed moss on the bottom. Seventy sexually mature \u003cem\u003eB. gaini\u003c/em\u003e were recorded in March 2020 from the deepest part of RP11.\u003c/p\u003e\u003cp\u003eRock pools RP12 and RP13 \u0026ndash; two smaller ponds are located nearby (Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e13\u003c/span\u003ec). RP12 measures 4 \u0026times; 2 m, while RP13 is 2 \u0026times; 1 m. Both have irregular polygonal shapes and depths of 0.2\u0026ndash;0.3 m. Their walls are coated with thin cyanobacterial mats, which reached 2 mm in places. In March 2020, 11 adult \u003cem\u003eB. gaini\u003c/em\u003e were recorded in RP12 and five in RP13.\u003c/p\u003e\u003cp\u003eOther shallow rock pools occur in the area, but those with abundant semi-decomposed moss did not contain anostracans.\u003c/p\u003e\u003cp\u003e\u003cb\u003e11. Maly Berthelot Island\u003c/b\u003e (unofficial name, an officially unnamed) is part of the Berthelot Islands group (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e8\u003c/span\u003ea). It lies in the Bellingshausen Sea, 11 km southeast of Galindez Island and about 5 km from the continental coast of the Kyiv Peninsula.\u003c/p\u003e\u003cp\u003eThe pond P10, elongated in shape, is located on an elevation in the northern part of the island, at 39 m a.s.l. (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e8\u003c/span\u003ed). It measures 20 \u0026times; 5 m with a depth of 0.5 m. The stony bottom is partly covered with decomposed and semi-decomposed moss, while the walls bear patches of brown cyanobacterial mat up to 2 mm thick. Eighty-three adult \u003cem\u003eB. gaini\u003c/em\u003e were recorded here in March 2020.\u003c/p\u003e\u003cp\u003eRock pool RP14 lies on the central highlands of the island at 41 m a.s.l. It has a shape resembling the letter W, measuring 5 \u0026times; 2 m with a depth of 0.2 m. The stony bottom is covered with decomposed and semi-decomposed moss. Along the pond margins, moss fills the space from bottom to surface, leaving only a central opening of free water where anostracans concentrate. The walls are coated with a thick brown cyanobacterial mat.\u003c/p\u003e\u003cp\u003eSeveral smaller rock pools (RP15\u0026ndash;17) are located nearby. They vary in shape, measure only a few square meters, and reach depths of up to 0.2 m. Their stone bottoms hold semi-decomposed moss, and their walls are covered with cyanobacterial mats. In March 2020, sexually mature \u003cem\u003eB. gaini\u003c/em\u003e were recorded in all four ponds: 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\u003eThe pond P12 is situated on the western part of the island, 15 m inland from the shore, at 5 m a.s.l. It measures 10 \u0026times; 4 m with a depth of up to 0.4 m. The stone walls and the bottom (to a depth of 30 cm) are coated with a 2\u0026ndash;3 mm thick brown cyanobacterial mat. The bottom also contains abundant silt from decomposed moss (Fig.\u0026nbsp;\u003cspan refid=\"Fig15\" class=\"InternalRef\"\u003e14\u003c/span\u003eb), while semi-decomposed and fresh moss occur near the shore. In February 2020, 37 \u003cem\u003eB. gaini\u003c/em\u003e individuals were recorded here (28 adults and 9 juveniles).\u003c/p\u003e\u003cp\u003eThe influence of environmental and biotic factors on the occurrence of \u003cem\u003eB. gaini\u003c/em\u003e was evaluated using nonparametric tests. The Mann\u0026ndash;Whitney\u0026ndash;Wilcoxon test indicated that depth significantly affected the likelihood of encountering \u003cem\u003eB. gaini\u003c/em\u003e (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). On average, the species was found more frequently in deeper water bodies. Nevertheless, \u003cem\u003eB. gaini\u003c/em\u003e was present across the full depth range studied (0.1\u0026ndash;1.0 m), although it was recorded only once at the shallowest depth of 0.1 m. In contrast, water temperature and salinity had no significant effect on the probability of occurrence; both variables showed only narrow ranges of variation across the studied sites.\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 analyses revealed no significant association between the presence of \u003cem\u003eB. gaini\u003c/em\u003e and the presence of \u003cem\u003eB. poppei\u003c/em\u003e (_χ\u0026sup2;_1\u0026thinsp;=\u0026thinsp;2.797, p\u0026thinsp;=\u0026thinsp;0.0944), month of sampling (_χ\u0026sup2;_3\u0026thinsp;=\u0026thinsp;0.853, p\u0026thinsp;=\u0026thinsp;0.3557), or year of sampling (_χ\u0026sup2;_3\u0026thinsp;=\u0026thinsp;3.416, p\u0026thinsp;=\u0026thinsp;0.0646). In contrast, the presence of cyanobacterial mats had a significant positive effect on the occurrence of \u003cem\u003eB. gaini\u003c/em\u003e (_χ\u0026sup2;_1\u0026thinsp;=\u0026thinsp;4.255, p\u0026thinsp;=\u0026thinsp;0.0391). However, this result should be interpreted with caution, as reservoirs lacking mats were rare (n\u0026thinsp;=\u0026thinsp;6), and \u003cem\u003eB. gaini\u003c/em\u003e was absent from all of them.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe investigated the distribution of \u003cem\u003eB. gaini\u003c/em\u003e in freshwater reservoirs across the islands and capes of the Antarctic coast within the Wilhelm Archipelago. Our study area extended\u0026thinsp;~\u0026thinsp;25 km north\u0026ndash;south (Hovgaard Island to the Berthelot Islands) and ~\u0026thinsp;22 km west\u0026ndash;east (Cruls Islands to the continental coast), enabling us to obtain new data on the freshwater fauna of this Antarctic region.\u003c/p\u003e\u003cp\u003eLong-term surveys showed that the number of reservoirs and islands with \u003cem\u003eB. gaini\u003c/em\u003e records increased over time (years: 2007 \u0026rarr; 2008 \u0026rarr; 2010 \u0026rarr; 2020; reservoirs: 2 \u0026rarr; 3 \u0026rarr; 6 \u0026rarr; 27; islands: 2 \u0026rarr; 3 \u0026rarr; 6 \u0026rarr; 9). Although some islands and reservoirs were resampled across years, the overall trend remains. This pattern reflects increased sampling effort (studied reservoirs: 8 \u0026rarr; 7 \u0026rarr; 18 \u0026rarr; 111; studied islands/capes: 5 \u0026rarr; 6 \u0026rarr; 13 \u0026rarr; 23). An important driver of new records was the work of hydrobiologists at the Ukrainian Antarctic Akademik Vernadsky Station on Galindez Island: the first author\u0026rsquo;s surveys in 2007\u0026ndash;2008 effectively initiated modern research on this crustacean in the region, which then expanded. Because \u003cem\u003eB. gaini\u003c/em\u003e was first described in 1910 from Petermann Island and nearby islets of the Wilhelm Archipelago (Daday de De\u0026eacute;s 1910), rapid colonization during only the 14 years of our study (2007\u0026ndash;2020) is unlikely; rather, the species has had\u0026thinsp;~\u0026thinsp;100 years to occupy suitable habitats (Polishuk et al. \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Chernov et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). On the other hand, we did not detect \u003cem\u003eB. gaini\u003c/em\u003e on 15 surveyed islands/capes that appear environmentally suitable, and even on islands with records, some water bodies lacked the species. Overall, \u003cem\u003eB. gaini\u003c/em\u003e is a common regional species that appears to be gradually expanding within available habitats.\u003c/p\u003e\u003cp\u003eTo interpret the current distribution of the southernmost anostracan, we first consider the species\u0026rsquo; origin in Antarctica (Rogers et al. \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2020b\u003c/span\u003e). Two hypotheses have been discussed: (i) Antarctic endemism and (ii) colonization from other regions. Most authors reject strict endemism because resting eggs are unlikely to remain viable through centuries of freezing, and because the active life-cycle phase of \u003cem\u003eB. gaini\u003c/em\u003e occurs in summer under liquid water and positive temperatures (Jurasz et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1983\u003c/span\u003e). This seasonal activity is supported by the species\u0026rsquo; metabolic eurythermy (Peck \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Pociecha \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2007\u003c/span\u003e) and contrasts with many Antarctic terrestrial invertebrates that have slow life cycles. Thus, \u003cem\u003eB. gaini\u003c/em\u003e is not a classic Antarctic specialist; instead, it relies on general anostracan adaptations \u0026ndash; resistant resting eggs, passive dispersal, and physiological flexibility of larvae, juveniles, and adults (Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Although its detritivores feeding differs somewhat from the filter-feeding typical of many \u003cem\u003eBranchinecta\u003c/em\u003e (Hawes \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2008\u003c/span\u003e), its life-history strategy does not indicate unique Antarctic adaptation (Peck et al. \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2006\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eResting eggs of \u003cem\u003eB. gaini\u003c/em\u003e were most likely transported from Chilean freshwater bodies to island groups (Falkland Islands, South Georgia, South Orkney Islands, South Shetland Islands) and directly to Antarctica (e.g., James Ross Island) via passive dispersal vectors. Colonization probably proceeded both from South America and via stepping-stone islands, and movements were not strictly unidirectional (Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Subsequent gradual range expansion likely occurred from James Ross Island toward Marguerite Bay, where environmental conditions permitted persistence (Hawes \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2008\u003c/span\u003e), with local population establishment following each successful dispersal event (Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). The prevailing colonization model posits that \u003cem\u003eB. gaini\u003c/em\u003e spread as resting eggs during the last\u0026thinsp;~\u0026thinsp;10,000 years after the Penultimate (Last) Glacial Maximum (20,000\u0026ndash;18,000 BP) (Ralph \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e1967\u003c/span\u003e). Early evidence included egg microfossils dated to ~\u0026thinsp;4200 BP on James Ross Island (Bj\u0026ouml;rck et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1996\u003c/span\u003e) and ~\u0026thinsp;5500 BP on Signy Island, South Orkney Islands (Jones et al. \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2000\u003c/span\u003e), later extended to ~\u0026thinsp;9300 BP on Horseshoe Island, Marguerite Bay (Hodgson et al. \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). More recently, COI molecular-clock analyses and geographic haplotype patterns suggest that \u003cem\u003eB. gaini\u003c/em\u003e may have survived the last glacial period in an as-yet unidentified Antarctic refugium (Pokorn\u0026yacute; et al. \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eSecondly, the species must not only disperse but also survive and establish in new territories. This may be achieved less through specific adaptations to extreme Antarctic conditions than through general biological traits common to anostracans. Below we consider the main factors that can limit or promote the spread of \u003cem\u003eB. gaini\u003c/em\u003e:\u003c/p\u003e\u003cp\u003e1) \u003cem\u003eBranchinecta gaini\u003c/em\u003e tolerates wide fluctuations in abiotic conditions, with temperature being the most critical. Its physiological flexibility allows it to withstand variations of up to 50\u0026deg;C. Adults survive up to 25\u0026deg;C in summer, while overwintering eggs remain viable down to \u0026minus;\u0026thinsp;25\u0026deg;C (Peck \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Adults lack antifreeze proteins, and hemolymph crystallizes at \u0026minus;\u0026thinsp;5\u0026deg;C (Hawes et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). With ongoing climate warming, habitats are gradually changing, providing longer periods of favorable conditions for growth, feeding, and reproduction.\u003c/p\u003e\u003cp\u003eTemperature also influences oxygen availability. Oxygen demand increases with temperature, while under ice cover metabolic rates decline, enabling survival despite hypoxia (Pociecha \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). During March\u0026ndash;April 2020, we observed living individuals under ice for up to three weeks in ponds on Uruguay and Irizar Islands. This extended survival may allow later-maturing females to produce more overwintering eggs, increasing both population size and dispersal potential.\u003c/p\u003e\u003cp\u003eSalinity is another critical factor. Low concentrations may stimulate development, but seawater intrusions reaching\u0026thinsp;~\u0026thinsp;20 psu are lethal to all stages except eggs (Pociecha \u0026amp; Dumont \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Even slight increases in salinity strongly limit survival (Hawes et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2008\u003c/span\u003e) because the permeable cuticle leads to osmotic imbalance and desiccation (Ralph \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e1967\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e2) Another reason for the success of \u003cem\u003eB. gaini\u003c/em\u003e is the near absence of antagonistic interactions in Antarctic freshwaters. As the largest invertebrate present, it is defenseless against predators, yet fish are absent from inland waters (Trokhymets et al. \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) and invertebrate predators are rare (Laybourn-Parry \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). Predation is therefore limited to birds, such as Kelp Gulls (\u003cem\u003eLarus dominicanus\u003c/em\u003e) and South Polar Skuas (\u003cem\u003eStercorarius maccormicki\u003c/em\u003e), which we observed occasionally feeding on \u003cem\u003eB. gaini\u003c/em\u003e in ponds and rock pools around the Argentine Islands. Similar predation by waterfowl has been reported previously (Green et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2005\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eInterspecific competition is also minimal. \u003cem\u003eBranchinecta gaini\u003c/em\u003e overlaps only partly with the copepod \u003cem\u003eB. poppei\u003c/em\u003e in diet (small bacteria, large diatoms). Although both species co-occurred in some reservoirs (e.g., Grotto Island), our Chi-squared analysis showed no significant relationship between their presence and abundance.\u003c/p\u003e\u003cp\u003eParasites may also influence populations. The cestode \u003cem\u003eBranchiopodataenia arctowskii\u003c/em\u003e uses \u003cem\u003eB. gaini\u003c/em\u003e as an intermediate host, with gulls as definitive hosts (Jarecka \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e1984\u003c/span\u003e). This parasite is not Antarctic-endemic and also occurs in the Northern Hemisphere (Bondarenko \u0026amp; Kontrymavicius 2004). Although data are lacking for the Wilhelm Archipelago, observed gull and skua predation on \u003cem\u003eB. gaini\u003c/em\u003e suggests that parasite transmission may occur locally.\u003c/p\u003e\u003cp\u003e3) \u003cem\u003eBranchinecta gaini\u003c/em\u003e can form symbiotic associations with microorganisms. Recent studies describe phylosymbiosis in the microbiomes of anostracans, particularly on gills and in the gut, which may enhance survival in harsh environments (Schwob et al. \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e4) \u003cem\u003eBranchinecta gaini\u003c/em\u003e occurs in reservoirs across a wide range of trophic states. In our study, it was found in oligotrophic (e.g., L1 on Uruguay Island), mesotrophic, and even eutrophic water bodies (e.g., RP18 on Petermann Island). It also inhabits ponds with large amounts of decomposed moss, provided free water space remains above the substrate (e.g., RP14 on Maly Berthelot Island). Mann-Whitney-Wilcoxon tests indicated that \u003cem\u003eB. gaini\u003c/em\u003e was significantly more common in deeper waters.\u003c/p\u003e\u003cp\u003eWhile most populations occur in mesotrophic waters, unusual cases of gigantism have been reported in highly eutrophic ponds. On King George Island, specimens reached 28.1 mm (females) and 29.8 mm (males) in a penguin-influenced pond (Jurasz et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1983\u003c/span\u003e), far exceeding the typical 16 mm (Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). However, hypertrophic conditions appear lethal: during our study no \u003cem\u003eB. gaini\u003c/em\u003e were found in guano-rich ponds on Moot Island (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e15\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e5) \u003cem\u003eBranchinecta gaini\u003c/em\u003e has a flexible feeding strategy. It scrapes organic matter from substrates and manipulates detritus with appendages, often swimming belly-up while shredding and consuming particles (Hawes \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Gut contents include algae, cyanobacterial mats, fungi, protists, rotifers, tardigrades, mites, chironomids, and remains of \u003cem\u003eB. poppei\u003c/em\u003e and \u003cem\u003eB. gaini\u003c/em\u003e. This confirms it as a detritivore and benthic herbivore, but also capable of cannibalism and opportunistic predation (Paggi \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Pociecha \u0026amp; Dumont \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eWe directly observed both benthic scraping and suspension feeding in P11 on Petermann Island and L1 on Uruguay Island. Transparent water revealed individuals scraping cyanobacterial mats, while others swam belly-up, generating feeding currents and filtering suspended matter.\u003c/p\u003e\u003cp\u003e6) Survival is also supported by a univoltine life cycle, with one generation per year. On King George Island, eggs hatch in November, adults appear in December, and reproduction continues from January until freeze-over in May (Jurasz et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1983\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIn the Wilhelm Archipelago, harsher conditions shorten the cycle. Adults did not appear until January, and juveniles were still present in February alongside mature individuals. Reservoirs began freezing in late March 2020, and by early April adults were scarce (L1 on Uruguay Island). Thus, the active phase lasted 4\u0026ndash;5 months instead of six. Notably, juveniles dominated in March 2020, suggesting that some eggs may hatch prematurely in the year they are laid when shallow areas freeze \u0026ndash; a phenomenon also described by Jurasz et al. (\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1983\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e7) A critical adaptation is the production of resting eggs capable of cryptobiosis. These double-shelled eggs (Jurasz et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1983\u003c/span\u003e) survive freezing to \u0026minus;\u0026thinsp;25\u0026deg;C and desiccation (Peck \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). Large egg banks ensure mass hatching and facilitate dispersal (Brendonck \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1996\u003c/span\u003e). After hatching, rapid development produces new egg cohorts, reinforcing the cycle.\u003c/p\u003e\u003cp\u003eWe observed dense aggregations of adults in small pools drying down (e.g., RP11 on Grotto Island, ponds near Palmer Station). Such conditions likely promote mass oviposition, boosting local egg banks.\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=\"CR51\" class=\"CitationRef\"\u003e2009\u003c/span\u003e) and between different sexes (Jurasz et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1983\u003c/span\u003e; Pociecha \u003cspan citationid=\"CR56\" 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) Anthropogenic impacts are becoming increasingly relevant. Plastic pollution in the Maritime Antarctic alters behaviour and gene expression in \u003cem\u003eB. gaini\u003c/em\u003e, suggesting nanoplastics threaten biodiversity (Bergami et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The species is also sensitive to nanosized titanium dioxide (n-TiO₂), a common pollutant, and has been proposed as a biomonitor (Gonz\u0026aacute;lez-Aravena et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Additionally, it may serve as a bioindicator of oligotrophic ponds (De Los Rios et al. 2008).\u003c/p\u003e\u003cp\u003eThird, the species must also possess mechanisms of distribution. In anostracans, two main dispersal strategies are recognized (Jocqu\u0026eacute; et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2010\u003c/span\u003e): active dispersers, which can move independently into new habitats; passive dispersers, which require external vectors for transport.\u003c/p\u003e\u003cp\u003e\u003cem\u003eBranchinecta gaini\u003c/em\u003e belongs to the latter group, as it cannot actively move between freshwater bodies via seawater, land, or air. In Antarctica, its dispersal is therefore accidental and occurs through random transport of resting eggs. Such egg-mediated dispersal is common in many anostracans (Brendonck \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1996\u003c/span\u003e). Four passive dispersal vectors are relevant in Antarctic ecosystems (Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2009\u003c/span\u003e): anthrochory, hydrochory, anemochory, and zoochory. Below, we examine these in the context of \u003cem\u003eB. gaini\u003c/em\u003e.\u003c/p\u003e\u003cp\u003e1) Anthrochory refers to dispersal mediated directly or indirectly by humans. Although some authors dismiss this vector for \u003cem\u003eB. gaini\u003c/em\u003e (Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2009\u003c/span\u003e), our observations suggest it is plausible. Tourism in the Wilhelm Archipelago has increased in recent decades, with Petermann Island serving as a major landing point for thousands of visitors annually. At least one nearby pond (RP18) hosts \u003cem\u003eB. gaini\u003c/em\u003e. Tourists walking through such ponds could pick up sediment containing eggs on their boots, especially when mixed with penguin guano. If sediment remains sticky, eggs may not be removed while walking on snow. During boot cleaning before re-embarkation, eggs could then be washed into another water body.\u003c/p\u003e\u003cp\u003eThus, eggs may be transferred between ponds on the same island. Further transfer between islands is less likely, but possible. For instance, tourists sometimes move directly between Petermann and Great Yalour Islands without ship-based decontamination. Mud with eggs could fall off boots onto snow, meltwater then carrying eggs into ponds. Yacht-based tourism increases the risk of introducing eggs to smaller surrounding islands. The same risk applies to inexperienced researchers who may not thoroughly wash their boots. Therefore, we argue that anthrochory could be an important dispersal vector, though this hypothesis requires experimental confirmation.\u003c/p\u003e\u003cp\u003e2) Hydrochory is dispersal by water. \u003cem\u003eBranchinecta gaini\u003c/em\u003e eggs may spread stochastically within islands but usually over short distances. Most reservoirs in this region are isolated, located in rock crevices or terraces. However, cascades of interconnected ponds do occur on Irizar, Eight, and Maly Berthelot Islands. During snow and ice melt, water may flow between reservoirs, carrying buoyant eggs to downstream habitats (Brendonck \u0026amp; Riddoch \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1999\u003c/span\u003e). Thus, hydrochory enables local dispersal but rarely long-distance spread.\u003c/p\u003e\u003cp\u003e3) Anemochory is dispersal by wind. Dried sediments containing eggs can be blown short distances between nearby rock pools (Brendonck \u0026amp; Riddoch \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1999\u003c/span\u003e). Long-distance aerial dispersal is considered unlikely (Vanschoenwinkel et al. \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). This mechanism would be restricted to shallow pools that dry completely during summer, leaving exposed egg-containing sediments vulnerable to wind transport. For example, this may occur between reservoirs on Maly Berthelot Island.\u003c/p\u003e\u003cp\u003e4) Zoochory is dispersal mediated by animals, particularly birds, and is likely the most important vector for \u003cem\u003eB. gaini\u003c/em\u003e. Birds frequently congregate around freshwater ponds for drinking, bathing, feeding, and resting (Viana et al. \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). In the Wilhelm Archipelago, potential vectors include the Kelp Gull, South Polar Skua, Antarctic Tern (\u003cem\u003eSterna vittata\u003c/em\u003e), and Snowy Sheathbill (\u003cem\u003eChionis albus\u003c/em\u003e). We observed Kelp Gulls and South Polar Skuas actively feeding on \u003cem\u003eB. gaini\u003c/em\u003e. Other studies also report predation by terns and skuas (Nedbalov\u0026aacute; et al. \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Zoochory occurs in two main forms: epizoochory and endozoochory (Hawes \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eEpizoochory involves external attachment of eggs. \u003cem\u003eBranchinecta gaini\u003c/em\u003e eggs can adhere to bird feet and feathers together with mud when birds bathe or feed. Such transport is known in other crustaceans (Trokhymets et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) and may occur both within and between islands. This mechanism is plausible given the abundance of nesting birds throughout the Wilhelm Archipelago. For instance, we observed South Polar Skuas flying\u0026thinsp;~\u0026thinsp;13 km between Locator and Galindez Islands, distances sufficient for egg transport.\u003c/p\u003e\u003cp\u003eEndozoochory involves ingestion of eggs, which survive passage through the digestive tract. Eggs may be swallowed incidentally with water or via predation on gravid females. After defecation, viable eggs can hatch in new habitats (Green \u0026amp; Figuerola \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Rogers \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). In other regions, egg transport has been demonstrated by insects (Beladjal \u0026amp; Mertens \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2009\u003c/span\u003e), fish (Beladjal et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2007\u003c/span\u003e), amphibians (Bohonak \u0026amp; Whiteman \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e1999\u003c/span\u003e), and birds (Green et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). In Antarctica, only birds are relevant, as other potential predators are absent. Thus, gulls, skuas, and terns are the most likely long-distance dispersal agents.\u003c/p\u003e\u003cp\u003eIn summary, \u003cem\u003eB. gaini\u003c/em\u003e occurs in freshwater bodies with cyanobacterial mats and detritus-rich bottoms. Its dispersal appears to depend on the presence of birds for zoochory and on water connections for hydrochory, but it is generally absent in ponds heavily influenced by penguin colonies. Within the Wilhelm Archipelago, the broad range of dispersal vectors supports colonization, with zoochory and hydrochory emerging as the most effective mechanisms.\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, ID, KJ, AZ, and PDLRE 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\u003eBauer DF (1972) Constructing confidence sets using rank statistics. JASA 67:687\u0026ndash;690. https://doi.org/10.1080/01621459.1972.10481279\u003c/li\u003e\n\u003cli\u003eBeladjal L, Mertens J (2009) Diaspore dispersal of Anostraca by flying insects. 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Materials of the second Kharkiv Conference on invertebrate zoology, Ukraine \u003cstrong\u003e(in Ukrainian)\u003c/strong\u003e\u003c/li\u003e\n\u003cli\u003eTrokhymets V, Gorobchyshyn V, Kozeretska I (2021) Population features of \u003cem\u003eBoeckella poppei\u003c/em\u003e in Lake Wujka, King George Island. UAJ 1:117\u0026ndash;122. https://doi.org/10.33275/1727-7485.1.2021.670\u003c/li\u003e\n\u003cli\u003eTrokhymets 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\u0026ndash;855. https://doi.org/10.1007/s00300-022-03040-5\u003c/li\u003e\n\u003cli\u003eTrokhymets V, Zinkovskyi A, Dykyy I (2024) Distribution of \u003cem\u003eBoeckella poppei\u003c/em\u003e (Copepoda: Centropagidae) in the region of the Wilhelm Archipelago (Kyiv Peninsula, Maritime Antarctica). Polar Biol 47:349\u0026ndash;365. https://doi.org/10.1007/s00300-024-03238-9\u003c/li\u003e\n\u003cli\u003eVanschoenwinkel 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\u0026ndash;134. https://doi.org/10.1111/j.2007.0030-1299.16349.x\u003c/li\u003e\n\u003cli\u003eViana DS, Santamar\u0026iacute;a L, Michot TC, Figuerola J (2013) Migratory strategies of waterbirds shape the continental-scale dispersal of aquatic organisms. Ecography 36(4):430\u0026ndash;438. https://doi.org/10.1111/j.1600-0587.2012.07588.x\u003c/li\u003e\n\u003cli\u003eWeller MW (1975) Notes on formation and life of ponds of the Falkland Islands and South Georgia. 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":false,"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":"polar-biology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pobi","sideBox":"Learn more about [Polar Biology](http://link.springer.com/journal/300)","snPcode":"300","submissionUrl":"https://submission.nature.com/new-submission/300/3","title":"Polar Biology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Zoogeography, Branchiopods, Freshwater crustaceans, Antarctica","lastPublishedDoi":"10.21203/rs.3.rs-7830481/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7830481/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 invertebrate animal in Antarctic freshwater bodies. This crustacean species playing important role in Antarctic ecosystems, was first recorded in the freshwater ponds of Petermann Island (Wilhelm Archipelago, Maritime Antarctica) during the Second French Antarctic Expedition of Jean-Baptiste Charcot in 1909. More complete official information about the distribution of this crustacean within this region of Antarctica is almost absent. Thus, present work aims to investigate the current distribution of \u003cem\u003eB. gaini\u003c/em\u003e in the region of Argentine Islands \u0026ndash; southern part of this archipelago. During multiyear sampling effort covering 2007, 2008, 2010 and 2020 expeditions, \u003cem\u003eBranchinecta gaini\u003c/em\u003e was found in 32 freshwater bodies of 12 islands of the Wilhelm Archipelago region and for the first time in reservoirs of 11 islands.\u003c/p\u003e","manuscriptTitle":"Distribution of Branchinecta gaini (Branchiopoda: Anostraca) in the area of the Wilhelm Archipelago (Maritime Antarctica)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-19 17:18:12","doi":"10.21203/rs.3.rs-7830481/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-07T16:48:53+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-22T00:43:26+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"336021489437667720383991873103998689705","date":"2025-11-24T14:54:36+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-18T17:27:29+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"40964600300506053557545932897250185375","date":"2025-11-18T15:08:31+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-10T14:20:18+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-10T14:12:29+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-22T02:33:05+00:00","index":"","fulltext":""},{"type":"submitted","content":"Polar Biology","date":"2025-10-10T23:48:52+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"polar-biology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pobi","sideBox":"Learn more about [Polar Biology](http://link.springer.com/journal/300)","snPcode":"300","submissionUrl":"https://submission.nature.com/new-submission/300/3","title":"Polar Biology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"9bc20fd5-fb58-4a5c-ac62-6a2cf1b9f87c","owner":[],"postedDate":"November 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-27T23:08:29+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-19 17:18:12","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7830481","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7830481","identity":"rs-7830481","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}