The westernmost record of the scyphomedusa Cassiopea andromeda in the Mediterranean: marine citizen science contributions to invasive species detection and monitoring

The westernmost record of the scyphomedusa Cassiopea andromeda in the Mediterranean: marine citizen science contributions to invasive species detection and monitoring | 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 The westernmost record of the scyphomedusa Cassiopea andromeda in the Mediterranean: marine citizen science contributions to invasive species detection and monitoring Macarena Marambio, Maria Pascual-Torner, Uxue Tilves, Alejandra Pérez, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6628928/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 30 Sep, 2025 Read the published version in Environmental Management → Version 1 posted 11 You are reading this latest preprint version Abstract The Mediterranean Sea, although a biodiversity hotspot, is one of the most affected seas by non-indigenous species (NIS). This problem is worsened by rising sea temperatures due to climate change, which promotes the spread of thermophilic species. Among the NIS scyphozoan jellyfish species recorded in the Mediterranean, Cassiopea andromeda – commonly known as the "upside-down jellyfish"– is a notable example. Observadores del Mar ( OdM ) is the leading platform for marine citizen science in Spain and works towards ocean conservation and health. It is a well-established tool for generating knowledge in marine research and has successfully provided early warning of NIS reports in the Mediterranean, while also serving as an effective network for the monitoring of NIS and other indicators. Three reports of C. andromeda from Almeria, southern Spain have been reported in OdM and thanks to the involvement of its community, 12 samples were collected for phylogenetic analysis and monitoring was done for 15 months in the study area. The results confirmed the first record of C. andromeda in Spanish Mediterranean waters representing the westernmost record in the basin. Monitoring also suggest the species establishment in the area. This study contributes to the knowledge of C. andromeda invasiveness and highlights the importance of marine citizen science in the detection and monitoring of NIS. It also underscores the collaboration and commitment already established between scientists and citizens, which will allow further progress in the fields of biological invasions, management, and policy. NIS Lessepsian invasion climate change geographical spread participatory science thermophilic jellyfish. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction The Mediterranean Sea, listed as one of the main hotspots in the world, is home to more than 17,000 marine species, accounting for 7% of the world’s total species (Coll et al. 2010 ). However, this biodiversity is changing because of various human-mediated impacts, such as species introduction, direct or indirect, among others (Coll et al. 2010 ; Stock et al. 2018 ). In particular, the presence of non-indigenous species (NIS), also called exotic, non-native, or alien species, has been used as a biodiversity loss indicator (Katsanevakis et al. 2014 ), and invasive alien species are considered one of the major threats to marine biodiversity (Bax et al. 2001 ; Zenetos et al. 2012 ; Evans et al. 2015 ). The Mediterranean Sea is one of the most affected seas by biological invasions (Zenetos et al. 2010 ). Recent studies have listed over 950 alien species introduced into the Mediterranean (Zenetos et al. 2020 ), a fact that has been favored since the opening of the Suez Canal in 1869 (Galil 2012 ). The Suez Canal, indeed, is the main entry point for NIS into the Mediterranean (Katsanevakis et al. 2013 ; Galil et al. 2018 ), a phenomenon known as “lessepsian migration”. For jellyfish, scyphozoans in particular, there are records of 18 species in the Mediterranean (reviewed in Badreddine and Bitar 2020 ), and at least 5 of them are lessepsian migrants (Galil et al. 1990, 2013 , 2017 ): Rhopilema nomadica (Galil, Spannier and Ferguson 1990); Phyllorhiza punctata (Lendenfeld, 1884); Cotylorhiza erythraea (Stiasny, 1920); Marivagia stellata (Galil and Gershwin 2010); and Cassiopea andromeda (Forsskål, 1775). Cassiopea andromeda , native to the Red Sea and the Indo Pacific (Mariotini and Pane 2010), was the first lessepsian jellyfish species described after the opening of the Suez Canal. It was first sighted in Cyprus in 1903 (Mass 1903), and since then, it has been reported (at least punctually or repeatedly observed) in almost the entire eastern basin (Goy et al. 1988 ; Spanier 1989 ; Çevik et al. 2006 ; Schembri et al. 2010 ; Zenetos et al. 2011 ; Siokou et al. 2013 ; Yokes et al. 2018 ; Crocetta et al. 2021 ) (Fig. 1 ). Regarding the western basin, the presence of C. andromeda has been documented on rare occasions, and the only records come from northern Tunisia (Amor et al. 2015 ) and Sicily (Cillari et al. 2018 , Maggio et al. 2019 ). Later, Cassiopea sp. was reported in Mar Menor (Murcia, Spain) in 2017 (Rubio, 2017 ); however, it was an occasional grey-literature report of a single small individual without species identification. Within the genus Cassiopea (order Rhizostomeae), which contains several species (e.g., C. mayeri, C. frondosa, C. ornata, C. xamachana, C. andromeda ), C. andromeda is the only species reported in the Mediterranean Sea. Most reports in this area identify C. andromeda by morphology without confirming it through molecular barcoding (Cillari et al. 2022 ; Deidun et al. 2018 ; Çevik et al. 2006 ), except for that from Palermo, Sicily (Maggio et al. 2019 ). However, Cassiopea is considered a cryptic species, therefore identification based on physical characters such as the color or pattern of spots at the exumbrella, number of rhopalia, shape and number of mouth appendages, length of oral arms, or arrangement of canals in the umbrella, are not entirely reliable and rigorous, as they can be highly variable between individuals of the same species (Jarms and Morandini 2019 ). For this reason, the use of molecular tools such as 16S ribosomal RNA (16S) and mitochondrial cytochrome c oxidase subunit I (COI) gene identity is especially relevant in any study involving this genus (Muffet et al. 2023; Holland et al. 2004 ). C. andromeda is commonly known as the “upside down jellyfish” because it often lies on its umbrella surface to expose the symbiotic dinoflagellates of the genus Symbiodinium present in their oral arms to light to facilitate photosynthesis (Lampert et al. 2011 ). This species typically inhabits warm and well-illuminated shallow waters such as mangroves and seagrass beds and areas with muddy or sandy bottoms. Recent studies have presented records of C. andromeda in harbors, such as the case of Malta (Schembri et al. 2010 ) and Augusta and Palermo in Sicily (De Rinaldis et al. 2021 ; Cillari et al. 2018 , 2022 ). The upside-down jellyfish is considered an invasive species (Katsanevakis 2011 ), and like every invasive species, it may have an ecological impact, as it can proliferate rapidly, forming large blooms within a short time frame (Zenetos et al. 2011 ; Deidun et al. 2018 ). Additionally, it possesses certain characteristics that could facilitate its spread and establishment, particularly its high tolerance to salinity and temperature stress (Klein et al. 2019 ), and it is able to survive at 13°C (Deidun et al. 2018 ) but also at 36°C (Çevik et al. 2006 ). Moreover, increasing temperatures due to global change and high human density may enhance Cassiopea growth, probably because of higher nutrient availability (reviewed in Medina et al. 2021 ). On the other hand, it may also have a socio-economic impact affecting tourism and human health as it is considered a mid-stinging species; therefore, prevention and mitigation measures must be taken where it is present, as well as the development of species-specific stinging protocols (Ballesteros et al. 2023 ). With the rapid expansion of NIS in the Mediterranean, the use of early detection and warning tools is essential to prevent significant ecological and/or socio-economic impacts caused by the establishment of these species in marine ecosystems. Marine citizen science, volunteers participating in marine research (Thiel et al. 2014 ), is expanding and gaining great value (Earp and Liconti 2020 ). Evidence shows that it is a robust tool for providing scientific data for biodiversity conservation (McKinley et al. 2016 ), improving scientific monitoring at large scales (Bonney et al. 2009 ; Dickinson et al. 2010 ), and contributing to research on biological invasions by acting as a tool for early detection of NIS (Delaney et al. 2008 ; Crall et al. 2010 ; Giovos et al. 2019 ; Tiralongo et al. 2020 ; Encarnação et al. 2021). Observadores del Mar ( OdM ; www.observadoresdelmar.es ) , the marine citizen science platform of reference in Spain, is focused on marine conservation, answering questions to improve the understanding of marine ecosystems, and working beyond ocean health. Currently, the platform houses 15 projects addressing five relevant topics: marine biodiversity, vulnerable species, marine impacts, climate change, and exotic and invasive species. OdM has managed to establish a very committed community in its 13 years of experience made up of several actors: scientific expert teams, stakeholders, collaborating organizations, the Sentinel Observatory network and the large community of volunteers. The Sentinel Observatory ( SO ) network was created in 2016, currently comprising over 20 diving centers and clubs, associations, and other entities. The objective of this SO network is to establish a more systematic data collection and monitoring by expanding even more the spatio-temporal range, therefore, acting as an early alert and becoming a functional network. The SO network goes one step further in their commitment with OdM by systematically monitoring one or more projects on the platform through increased sampling, project-specific dives, or research into a particular data. They report on a recurring basis and OdM provides them with specific training and a more constant and dedicated exchange of information. OdM 's commitment and dedication is not only to the SO network, but to the community in general, with the aim of providing with sufficient tools to ensure the correct collection and veracity of data, to analyze and obtain results and answers to the research questions. For this reason, different materials have been developed and made available, including identification guides, a large photo database accessible to participating citizens, adapted standardized protocols, online and in-person training, as well as validation by an expert scientific team, resulting in high scientific value and an excellent-quality database (Figuerola-Ferrando et al. 2024; Coppari et al. 2024 ). As for jellyfish research, various initiatives have demonstrated the effectiveness of citizen science (reviewed in Marambio et al. 2021 ), some of which provide valuable information about the ecology, spatio-temporal distribution, and the socio-economic impact in certain coastal areas (De Donno et al. 2014 , Kienberger and Prieto 2017 , Marambio et al. 2021 ; Tirelli et al. 2021 ). In OdM , one of the most successful projects is the “ Jellyfish Alert” (Marambio et al. 2023 ), which has been part of the platform since its creation in 2012 and currently has a very active community. The project is focused on data collection related to the presence and absence of gelatinous zooplankton organisms, including “true jellyfish” species, native and non-native, hydrozoans, ctenophores and salps. Data of one or few individuals and blooms are commonly registered, and records come mainly from the Mediterranean but also from around the world. In the years that the project has been active, a database of more than 2500 observations has been created including valuable records of the species present mainly on the Spanish coast. Recently, a protocol for monitoring climate change indicator species has been included in the project to collect data more systematically and help understand the effects of rising sea temperatures on the population and reproductive cycles of some common Mediterranean jellyfish species. This study aims to report the first phylogenetically confirmed record of the scyphomedusa C. andromeda (Forsskal, 1775) in Spanish waters and the westernmost record of the species in the Mediterranean Sea, which has formed large aggregations of a self-sustained reproductive population and has remained established in the last year, even expanding its distribution in the waters of the Aguadulce Marina in Almeria, southern Spain. Furthermore, this work emphasizes the importance of marine citizen science initiatives such as OdM and the involvement of its community in reporting the presence of the species, collecting samples for further scientific analyses, and monitoring the population with a temporarily systematic approach. Materials and methods Study area The Marina Aguadulce is located at 36° 48.51’ N and 2° 33.42’ W, in the town of Roquetas de Mar, 8 km from Almería, province of the Autonomous Community of Andalusia in Spain (Fig. 2 ). It is mainly a touristic port with a total area of 170,462 m 2 and more than 750 moorings available. The sides of the different channels of the marina are formed by rocks, but the central part is made of silt (approximately 15 cm deep) and has an approximate width of 5–8 m depending on the channel. Record, sample collection and monitoring Three observations (March 2021, February 2023 and December 2023) of Cassiopea individuals were registered in the Jellyfish Alert project in the OdM platform by one SO of the network. The last record, from December 2023, corresponded to an aggregation of considerable abundance, therefore the expert scientific team considered it relevant to carry out a phylogenetic analysis as it is a cryptic NIS. For this purpose, twelve Cassiopea individuals of approximately 5 cm umbrella diameter were hand-collected by scuba divers at various locations (Fig. 2 ) within the study area on February 11 and 12, 2024. Temperature and salinity were recorded in each sampling point. The rationale for collecting twelve individuals distributed along the Marina Aguadulce was to account for the possibility of more than one species coexisting, as other studies have detected for Cassiopea (Muffet et al. 2023). After collection, the specimens were preserved in 96% ethanol at room temperature and analyzed three days later. Monitoring was carried out for 15 months, since the first detection in December 2023 until February 2025, and consisted of observing the presence or absence of Cassiopea in each of the seven channels that comprise the marina, as well as in the entrance channel, to assess its establishment and adaptation in the study area. Additionally, during the monitoring conducted in December 2023, population density was estimated in one of the seven channels (4 m wide × 50 m long) (corresponding to T4 in Fig. 2 ), using 1x1m quadrants. The umbrella diameter of 52 specimens was measured to estimate a rough size range. DNA sequencing DNA was extracted from each of the twelve Cassiopea specimens from a small portion of the umbrella margin following the standard phenol‒chloroform protocol. The quantity of DNA was assessed using Nanodrop, and its quality was checked via agarose 1% gel electrophoresis. Mitochondrial cytochrome c oxidase subunit I (COI) and 16S ribosomal RNA (16S) were amplified using primers ‘LCO1490-JJ2’ (5′-CHACHACWAAYCAYAARGAYATYGG-3′) and ‘HCO2198-JJ2’ (5′-ANACTTCNGGRTGNCCAAARAATCA-3′) for COI and ‘C&B1’ (5′-TCGACTGTTTACCAAAAACATAGC-3′) and ‘C&B2’ (5′-ACGGAATGAACTCAAATCATGTAAG-3′) for 16S, as described by Gamero-Mora et al. ( 2022 ). The polymerase chain reaction (PCR) involved 5 min at 94°C for initial denaturation, followed by 35 cycles of amplification (denaturation at 94°C for 15 s, annealing at 53°C for 15 s and elongation at 72°C for 45 s) and a final extension for 5 min at 72°C. The PCR products were validated through 1% gel electrophoresis, purified by 1:5 dilution and Sanger sequenced at Stab Vida S. A. Data analysis The 16S and COI sequences from the 12 individuals in Almeria Harbor collected in this study were aligned using the 'msa' function (from the 'msa' package) with other Cassiopea sequences available in the GenBank database: C. andromeda, C. xamachana, C. mayeri, C. culionensis , and C. frondosa , as well as with the outgroup species Mastigias papua and P. punctata (Table 1 ). The alignments were trimmed to 546 bp for 16S and 514 bp for COI using 'msaTrim' (from the 'microseq' package). Phylogenetic analyses were conducted separately for 16S and COI using maximum likelihood as the optimality criterion for each. The optimal substitution model was selected via ModelFinder, choosing the model with the lowest Akaike information criterion (AIC) score: TIM2 + F + I + G4 for 16S and TIM2 + F + I for COI (Kalyaanamoorthy et al. 2017 ). Each optimal model was bootstrapped 1000 times to generate the final consensus phylogenetic tree with branch support values (Hoang et al. 2018 ). The phylogenetic analyses were performed via IQ-TREE multicore (ver. 2.3.2). The consensus trees were visualized in Rstudio (Rstudio, 2020 ) using the 'ggtree' package, which was previously rooted in the outgroup species M. papua with the 'root' function (from the 'ape' package). Results After genetic analysis of the twelve collected specimens, the results revealed that they corresponded to the species C. andromeda , becoming the first phylogenetically confirmed record of this species in Spain and the westernmost record of the Mediterranean basin. The observation was validated in the Jellyfish Alert project of the OdM platform as a confirmed record of C. andromeda species (Fig. 3 ). The other two previous observations, from March 2021 and February 2023, were validated only at the genus level because no phylogenetic analysis was performed. During the sampling in February 2024, the temperature ranged from 14.2 to 14.5°C, and the salinity ranged from 37.5–37.7. The aggregations of C. andromeda were observed in various channels, mainly in the central silt area, covering the length and width of the channels at an approximate depth of 4–5 m. Some of them were also observed over the meadows of another invasive species, the Rugulopteryx okamurae algae, which has also colonized areas of the Marina. No individuals were observed over the rocky lateral areas. Individuals were characterized by a whitish color with white and blue rounded and flattened vesicles (Fig. 3 ). During the monitoring carried out in December 2023, the density of the population was estimated to be 80–100 individuals/m 2 and the size of the individuals ranged from 4–30 cm umbrella diameter. The monitoring conducted over 15 months indicated that the population has survived all seasons and has even expanded its distribution, having already colonized all the marina channels by 2025 (Fig. 4 ). Moreover, different stages and sizes of individuals have been observed, indicating active reproduction in the study area. Phylogenetic analyses of the 12 sequences of Cassiopea from Almeria, Spain, combined with 24 additional sequences (most of which are available in the GenBank database), confirmed that Cassiopea specimens from Almeria clearly belong to C. andromeda . Four COI sequences, although matching the species, showed nucleotide variations likely due to Sanger sequencing errors and were therefore excluded from the analyses to include only high-quality sequences. All specimens were clearly grouped within the clade of C. andromeda , which also includes specimens from Egypt, Florida Keys, and Sicily. At the same time, the phylogenetic tree revealed the presence of other clades, such as C. xamachana , which was closest to C. andromeda , along with C. culionensis, C. ornata, C. mayeri , and C. frondosa . The bootstrap values for most nodes of the tree were greater than 80%, indicating that the consensus maximum likelihood tree was highly reliable (Fig. 5 ). Sequences from Almeria were identical to the two sequences from Florida, except for one COI sequence and four 16S sequences. However, the molecular distance, measured by the Kimura 2-parameter (K80), among the sequenced individuals remained very low (0.2 ± 0.2% for 16S and 0.0 ± 0.1% for COI). These values did not differ from those of C. andromeda from Egypt, Florida, and Sicily (16S: 0.2 ± 0.2% and COI: 0.2 ± 0.3%). The intraspecific variation in C. andromeda (16S: 0.2 ± 0.2% and COI: 0.2 ± 0.3%) was much smaller than the interspecific variation (16S: 11.2 ± 5.1 and COI: 14.3 ± 6.0%). Accordingly, all these groups presented high genetic distance from the outgroup species M. papua and P. punctata (16S: 21.0 ± 1.5% and COI: 25.1 ± 1.9%) (Supplementary Information file). Table 1 Sequences of the mitochondrial ribosomal gene 16S rRNA and the mitochondrial protein-encoding gene cytochrome c oxidase I (COI) were used for phylogenetic analysis. Species with ‘*were reported as C. frondosa in the sequence publication but fall into the C. xamachana clade, which is supported by Muffet et al. (2023). ‘^’ indicates that the sequences are not available in GenBank and were given by the authors. GenBank accession numbers of sequences in bold were obtained in this study Species Location 16S Genbank Accession COI Genbank Accession Source Cassiopea andromeda El Ghardaqa, Egypt - AY319458 Holland et al 2004 Cassiopea andromeda Baja California Sur, Isla San Jose, Mexico KY610611 KY610551 Daglio et al. 2017 Cassiopea andromeda Cudjoe Key, Florida, USA OP503932 OP503345 Muffet et al. 2023 Cassiopea andromeda Key Largo, Florida, USA OP503939 OP503367 Muffet et al. 2023 Cassiopea andromeda Almería, Spain CSA331484 - This study Cassiopea andromeda Almería, Spain CSA331485 CSA331497 This study Cassiopea andromeda Almería, Spain CSA331486 CSA331498 This study Cassiopea andromeda Almería, Spain CSA331487 CSA331499 This study Cassiopea andromeda Almería, Spain CSA331488 - This study Cassiopea andromeda Almería, Spain CSA331489 CSA496001 This study Cassiopea andromeda Almería, Spain CSA331490 - This study Cassiopea andromeda Almería, Spain CSA331491 CSA496003 This study Cassiopea andromeda Almería, Spain CSA331492 CSA496004 This study Cassiopea andromeda Almería, Spain CSA331493 CSA496005 This study Cassiopea andromeda Almería, Spain CSA331494 - This study Cassiopea andromeda Almería, Spain CSA331495 CSA496007 This study Cassiopea andromeda Palermo, Sicily - Ca2_CaCOIF^ Maggio et al. 2019 Cassiopea andromeda Palermo, Sicily - Ca1_CaCOIF^ Maggio et al. 2019 Cassiopea andromeda Palermo, Sicily - Ca4_CaCOIF^ Maggio et al. 2019 Cassiopea culionensis Lapu-Lapu, City of Cebu, Philippines MW164869 MW160913 Gamero-Mora et al. 2022 Cassiopea culionensis Lapu-Lapu, City of Cebu, Philippines MW164879 MW160923 Gamero-Mora et al. 2022 Cassiopea culionensis Lapu-Lapu, City of Cebu, Philippines MW164886 MW160930 Gamero-Mora et al. 2022 Cassiopea frondosa West Key, Florida, USA KY610617 AY319467 Holland et al. 2004 and Daglio et al. 2017 Cassiopea mayeri Ryukyu Islands, Okinawa, Japan MW164859 MW160931 Gamero-Mora et al. 2022 Cassiopea mayeri Lapu-Lapu, City of Cebu, Philippines MW164863 MW160934 Gamero-Mora et al. 2022 Cassiopea mayeri Lapu-Lapu, City of Cebu, Philippines MW164864 MW160935 Gamero-Mora et al. 2022 Cassiopea mayeri Calatagan, Luzon Island, Philippines MW164865 MW160936 Gamero-Mora et al. 2022 Cassiopea mayeri Calatagan, Luzon Island, Philippines MW164866 MW160937 Gamero-Mora et al. 2022 Cassiopea ornata Kakaban, Kalimantan, Indonesia AB720918 AY319472 Holland et al. 2004 and Gamero-Mora 2022 Cassiopea ornata Guam, USA OL721669 OL799293 Anthony et al. 2022 Cassiopea xamacana* Bahia Delfines, Bocas del Toro, Panama KY610613 KY610558 Gómez Daglio and Dawson 2017 Cassiopea xamacana* Bahia Delfines, Bocas del Toro, Panama KY610614 KY610559 Gómez Daglio and Dawson 2017 Cassiopea xamachana Tavernier, Florida, USA OP503922 OP503334 Muffet et al. 2023 Cassiopea xamachana Lobster Walk, Monroe County,Florida, USA OP503929 OP503341 Muffet et al. 2023 Mastigias papua Risong Cove, Palau KU901021 KU901397 Swift et al 2016 Phyllorhiza punctata Gulf of California, Mexico MT902932 MT904380 Rosales-Catalán et al 2021 Discussion According to Zenetos et al. ( 2020 ), almost 1000 marine NIS have been introduced into the Mediterranean. Although the number of alien species in the Mediterranean varies between regions (Zenetos et al. 2012 ), the majority occur in the Eastern sub-region. The Sicily Channel plays an important role in this distribution pattern since it has been traditionally considered a biogeographical barrier that prevents the spread of these species, restricting them to the eastern basin (e.g., Quignard and Tommasini 2000). Nevertheless, some species have crossed the Sicily channel and have been found in the western region. This is the case for some lessepsian scyphomedusae species, such as our target species C. andromeda (Morandini et al. 2017 ; Aljbour et al. 2017 ; Medina et al. 2021 ), and others, such as R. nomadica (Balistreri et al. 2017 )d punctata (Deidun et al. 2017 ). C. andromeda is one of the 18 species of jellyfish reported as NIS in the Mediterranean. Its records, although not all phylogenetically confirmed, are diverse. Until now, the species had not been confirmed in Mediterranean Spanish waters, and its westernmost record was from Italy (Maggio et al 2019 ). In this work, we report the first phylogenetically confirmed record of the NIS C. andromeda in Spanish waters and the westernmost record of this species in the Mediterranean Sea. The analysis suggests that the population in this location consists solely of C. andromeda (Fig. 5 ), excluding any coexistence with C. xamachana , as described in other studies (Muffet et al. 2023). Overall, the bootstrap values (an indicator of the confidence in the placement of a particular clade within a phylogenetic tree) were between 80% and 99%, with few values lower than 70%, in accordance with other phylogenetic studies of Cassiopea species (Muffet et al. 2023, Gamero-Mora et al. 2022 , Arai et al. 2017 ). When comparing the COI and 16S trees, the former had higher bootstrap values, except for the node between the clades C. ornata/C. culionensis and C. mayeri (63%). However, the bootstrap value of the analogous node in the 16S tree was greater (81%). Therefore, the phylogenetic results in this study are highly reliable. The phylogenetic tree, which uses either 16S or COI markers, indicates that each Cassiopea species diverged through distinct evolutionary paths, in accordance with other phylogenetic studies of Cassiopea (Gamero-Mora et al. 2022 ; Muffet et al. 2023). These trees show that C. frondosa is distinct from the other species, indicating early divergence. Interestingly, this is the only Cassiopea species that can be unequivocally identified by morphology (it has a different number of rhopalia) (Morandini et al. 2017 ). Later in evolution, there was a divergence into two distinct clades: the “ C. andromeda/C. xamachana '' and “ C. mayeri/C. ornata/C. culionensis ” clades, where C. mayeri diverged from the latter. Finally, C. andromeda - C. xamachana , and C. ornata - C. culionensis diverged from their most recent common ancestors, indicating recent evolution, and suggesting potential cryptic species within these groups (Fig. 5 ). Crypticity is common in Scyphozoa and can lead to species misidentification when it is detected only by morphology (Moura et al. 2022 ; Holland et al. 2004 ; Dawson et al. 2003). In the context of invasive species, crypticity complicates their detection and management, hampering the prediction and control of their impacts (Jarić et al. 2019 ). In that sense, when a species has been sighted in a new location, barcoding identification—alone or combined with morphological description—is indispensable to ensure correct identification and management. There is a large difference between naming a study species and labeling it with DNA barcodes (such as 16S or COI markers), with the latter being much more precise. In addition, if the generated DNA barcodes are stored in public databases, they may be available for future phylogenetic studies. For example, our phylogenetic tree revealed that Cassiopea from Panama, which Gomez Daglio and Dawson (2017) identified as C. frondosa , corresponds to C. xamachana , which is in accordance with the findings of Muffet et al. (2023). This fact, together with other examples of reidentification of Cassiopea species (Gamero-Mora et al. 2022 ), highlights how DNA barcoding allows species identification to be adapted in future studies, considering that taxonomy can change over time. The introduction pathway of C. andromeda into Spanish waters is unknown. As an epibenthic scyphozoan, this jellyfish has a very limited swimming capability, and most of the translocations reported in this species are more likely to be related to maritime transportation rather than natural transport by currents or by its own displacement (Holland et al. 2004 ; Schembri et al. 2010 ). We hypothesize that C. andromeda from this study, possibly the polyp stage, could have arrived by vessel transportation and probably as biofouling, since the study area is a marina and does not have ballast water loads. This hypothesis agrees with the case of Turkey, where the authors also suggested that polyps may have arrived in ships as biofouling (Çevik et al. 2006 ) while the pelagic stages in ballast water (Özgür and Öztürk 2008 ). Additionally, in Malta, the authors indicated the possibility that recreational vessels could be the vector for the introduction of this species (Deidun et al. 2018 ). In any case, independent of the arrival pathway, the current environmental conditions in the study area are certainly suitable for the species to develop and establish large populations, as has been observed in the last year after its first detection. The presence of this species in harbors and marinas has also been described in other areas, such as Malta, Sicily and Turkey (Schembri et al. 2010 ; Cillari et al. 2018 ; Çardak et al. 2011 , respectively). Harbors have been described as an ideal region for NIS introduction because of high maritime traffic (Ferrario et al. 2017 ) and, in the case of C. andromeda , it has been demonstrated that human-impacted coastal habitats may enhance its ability to sustain populations and contribute to its establishment (Çevik et al. 2006 ; Thé et al. 2023 ; Stoner et al. 2011 ). Following the history of invasive species in the Mediterranean, several authors have suggested that finding lessepsian species in the western basin may be considered an indicator of the warming trend of the Mediterranean Sea (Boero et al. 2009 ; Daly Yahia et al. 2013 ). Water warming facilitates the natural spread of tropical and subtropical species, enabling them to expand their distribution range (Lasram et al. 2008 ; Parravicini et al. 2015 ). In this context, the Mediterranean Sea stands out as one of the most significant and susceptible regions to climate change (Giorgi 2006 ; Lionello et al. 2012 ), experiencing a warming rate per decade that exceeds the global average by more than threefold. These climate change conditions, and the resulting increase in sea temperature, may support the distribution and establishment of thermophilic species such as C. andromeda (Çevik et al. 2006 ), which is considered to enhance its physiological response to global warming (Aljbour et al. 2017 , 2019 ; Banha et al. 2020 ), and whose thermal tolerance could promote an increase in the population and expansion of its geographic distribution range (Aljbour et al. 2019 ). C. andromeda records in the Mediterranean are from semi-enclosed eutrophic shallow waters with low hydrodynamics (Maggio et al. 2019 ). This is the case for the harbors mentioned above and for nature reserves (Malta, Deidun et al. 2018 ), marine protected areas (Tunisia, Amor et al. 2015 ), the cooling water drainage channel of a factory (Turkey, Çevik et al. 2006 ) or lagoons (Turkey, Özgür and Öztürk 2008 ). These shallow areas, although quite stressful (e.g., high temperatures/irradiation and potential extreme salinity changes), have been demonstrated to be suitable for their establishment, probably because of the high tolerance of this jellyfish to environmental variation (Morandini et al. 2017 ; Mammone et al. 2021 ). In previous works, it has been described at different temperatures ranging from 14.1–17.6°C in Palermo (Maggio et al. 2019 ), 13.36–14.49°C in Malta (Deidun et al. 2018 ), and 29–36°C in Turkey (Çevik et al. 2006 ; Özgür and Öztürk 2008 ). In this study, C. andromeda was first detected in winter (December‒February) when the water temperature was ~ 14.2°C and has been monitored and observed throughout the year following the yearly temperature range. The high abundances (80‒100 individuals/m 2 ) recorded in the present study, are much higher compared with other studies where the maximum abundances described were 30‒40 individuals/m 2 (Niggl and Wild 2010 ), especially considering that it is very likely that the density is underestimated since according to the information reported by the SO during the monitoring reporting, the jellyfish were one on top of the other forming layers that did not allow counting all the individuals in each quadrant. Marine citizen science, as a growing opportunity for marine research (Sandahl and Tottrup 2020; Earp and Liconti 2020 ; Changeux et al. 2020 ; García-Soto et al. 2021 ), has been reported in previous studies (Johansen et al. 2021 ; Marambio et al. 2021 ; Tirelli et al. 2021 ; Edelist et al. 2022 ; Dobson et al. 2023 ; Terenzini et al. 2023 ) as a highly valuable tool for increasing knowledge about jellyfish distribution. Additionally, it provides essential data for establishing and/or improving preventive programs to mitigate jellyfish impacts in some coastal areas. In recent years, another growing area of ​​citizen science is the reporting of NIS, therefore considered a useful tool for expanding the scale of data collection, for early detection and for monitoring exotic and invasive species (Delaney et al. 2008 ; Crall et al. 2010 ; Mannino and Balistreri 2018 ; Giovos et al. 2019 ; Tiralongo et al. 2020 ; Pocock et al. 2024 ). All this represents a clear benefit in expanding exotic and invasive species knowledge, and in their monitoring, management, and related policy development (Groom et al. 2019 ; Pysek et al. 2020 ; Price-Jones et al. 2022 ). Detecting NIS as early as possible, along with monitoring and research, is essential for determining the ecological and socio-economic impacts that their presence and establishment could have on invaded areas (Giovos et al. 2019 ; Pocock et al. 2024 ). In these instances, marine citizen science requires significant involvement from volunteers, as participation goes beyond mere observation reporting. Therefore, it is essential that platforms and initiatives have a track record and are well established, with strong community engagement. In this sense, OdM has a large and highly engaged community of volunteers from different sectors and a robust network of Sentinel Observatories ( SO ). Aquatours Almeria, the diving center that reported the presence of C. andromeda , has been part of this SO network since the beginning. In fact, 75% of the SO network consists of diving centers or clubs, which represents a good opportunity for marine citizen science, as divers are considered one of the most committed user groups, according to previous studies (Martin et al. 2016 , Lucrezi et al. 2018 ). Moreover, OdM has demonstrated its consistency in effectively contributing to the early detection of NIS, expanding knowledge, and contributing to decision-making related to marine conservation (Azzurro et al. 2013, 2020; Castejón-Silvo et al. 2023 ; Figuerola-Ferrando et al. 2023 ). The OdM platform, through its specific project “Jellyfish Alert”, provides the necessary identification clues and expert support to recognize jellyfish species easily under good conditions. However, in some cases phylogenetic analysis is required for a correct identification, especially for cryptic species such as Cassiopea individuals. When further analysis is needed, the close collaboration with the OdM ’s SO enables the collection of samples as they immediately receive a protocol from the scientific team with instructions for sample collection, ultimately allowing for species confirmation. Furthermore, as a SO of the platform's network, they regularly conduct structured monitoring at the same location during their year-round dives. This has allowed them to track the species for more than 12 months since its detection, and they have been able to observe and report on its reproduction and expansion in the colonized area. This will allow us to get valuable information to assess the impact of the species over time (Pocock et al. 2024 ). Moreover, with this confirmed record, the message can be expanded to the public and encourage attention to this species. It will also contribute to understanding the importance and impact of invasive species on marine ecosystems and contribute to adaptive management strategies within a citizen science approach (Giovos et al. 2019 ; Pocock et al. 2024 ). Conclusions The detection of NIS is highly relevant to the ecology of ecosystems and the conservation of the marine environment. The case of C. andromeda is of particular interest because it can be easily transported as biofouling and/or ballast water, and when it arrives in a new area, it can easily adapt to different environmental conditions, being highly thermotolerant. These characteristics, together with rising sea temperatures due to climate change, make almost any point in the Mediterranean a suitable place for this species, which, in addition, can spread rapidly, affecting local populations. This study contributes to the knowledge of the NIS C. andromeda in the Mediterranean, presenting the first phylogenetically confirmed record in Spanish waters and the westernmost record in the basin, as well as the contribution to public DNA databases. On the other hand, marine citizen science has proven useful and, if well implemented, is a powerful tool that allows the expansion of spatial-temporal marine research, improves ecological understanding, and contributes to ocean literacy-enhancing knowledge. In the case of NIS, it has an important value as a detection tool that has been used in various taxonomic groups, including jellyfish. For instance, the present study demonstrates the relevance of the marine citizen science platform OdM , as it plays a fundamental role in the detection, sampling and monitoring of this species through its engaged community. The potential of marine citizen science in reporting the presence of certain species and acting as a warning tool is unquestionable, as the advantage of having a large and engaged community makes it a highly cost-effective tool. This collaboration between scientists and citizens is translated into advances in marine research, management and even policy. With more than 12 years of experience, OdM has demonstrated the commitment of its community, the importance of providing training and standardized protocols, and the quality of the data. Furthermore, it implements all the recommendations for the establishment and successful development of a marine citizen science platform, and its contributions thus far confirm its success. Declarations Funding: This study has been supported by the LIFE IP Intemares project (LIFE15 IPE/ES/012) and the OdM Climate project supported by the Biodiversity Foundation of the Spanish Ministry for Ecological Transition and the Demographic Challenge, through the Call for projects that contribute to the implementation of the National Plan for Adaptation to Climate Change (2021-2030), and the PID2020-118394RB-100 project. All the authors affiliated to the Institut de Ciències del Mar (ICM-CSIC) acknowledge the support of the “Severo Ochoa Centre of Excellence" accreditation ( CEX2024-001494-S funded by AEI 10.13039/501100011033 ). Competing Interests: The authors have no relevant financial or non-financial interests to disclose. Conflict of interest: The authors declare no potential conflict of interest in the present work. Availability of data and materials: DNA sequences were submitted to GenBank (accession numbers: PQ154578–PQ154589 for 16S sequences and PV533755–PV533762 for COI sequences). Author Contributions Study Conceptualization and Investigation were performed by Macarena Marambio, Maria Pascual-Torner and Uxue Tilves. Data collection and Formal Analysis were performed by Macarena Marambio, Maria Pascual-Torner and Alejandra Perez. Writing of the original draft was performed by Macarena Marambio, Maria Pascual-Torner, Uxue Tilves. Review and editing of the manuscript were performed by Macarena Marambio, Maria Pascual-Torner, Uxue Tilves, Josep Maria Gili, Alejandra Perez and Ainara Ballesteros. Supervision of the study was performed by Macarena Marambio, Maria Pascual-Torner and Josep Maria Gili. All authors read and approved the final manuscript. Acknowledgments: The authors would like to thank all the citizen scientists involved in Observadores del Mar, as well as all the Sentinel Observatories of the platform, specially to Aquatours Almeria Aventuras Submarinas and all their staff for their implication and proactive attitude toward the sampling, monitoring and the research. We also thank Jose Maria Perez Freije from the University of Oviedo for his support on the genetic analysis. References Aljbour SM, Zimmer M, Kunzman A (2017) Cellular respiration, oxygen consumption, and trade-offs of the jellyfish Cassiopea sp. In response to temperature change. J Sea Res 128: 92–97. http://dx.doi.org/10.1016/j.seares.2017.08.006 Aljbour SM, Zimmer M, Al-Horani FA, Kunzman A (2019) Metabolic and oxidative stress responses of the jellyfish Cassiopea sp. To changes in seawater temperature. J Sea Res 145: 1–7. 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The upside-down jellyfish Cassiopea xamachana as an emerging model system to study cnidarian-algal symbiosis. In: A Boutet, B Schierwater (ed) Handbook of Marine Model Organisms in Experimental Biology: Established and Emerging. CRC, Boca Raton (FL), pp 149–71 Morandini AC, Stampar SN, Maronna MM, Da Silveira FL (2017) All non-indigenous species were introduced recently? The case study of Cassiopea (Cnidaria: Scyphozoa) in Brazilian waters. J Mar Biol Assoc U K 97(2): 321–328. https://doi.org/10.1017/S0025315416000400 Moura CJ, Ropa N, Magalhães BI, Gonçalves JM (2022) Insight into the cryptic diversity and phylogeography of the peculiar fried egg jellyfish Phacellophora (Cnidaria, Scyphozoa, Ulmaridae). PeerJ 10:. https://doi.org/10.7717/peerj.13125 Muffett K, Miglietta MP (2023) Demystifying Cassiopea species identity in the Florida Keys: Cassiopea xamachana and Cassiopea andromeda coexist in shallow waters. PLoS One 18:. https://doi.org/10.1371/journal.pone.0283441 Niggl W, Wild C (2010) Spatial distribution of the upside-down jellyfish Cassiopea sp. within fringing coral reef environments of the Northern Red SEa: implications for its life cycle. Helgol Mar Res 64: 281–287. DOI 10.1007/s10152-009-0181-8 Özgür E, Öztürk B (2008) A population of the alien jellyfish, Cassiopea andromeda (Forsskål, 1775) (Cnidaria: Scyphozoa: Rhizostomea) in the Ölüdeniz Lagoon, Turkey. Aquat Invasions 3(4):423–428. http://dx.doi.org/10.3391/ai.2008.3.4.8 Parravicini V, Mangialajo L, Mousseau L, Peirano A, Morri C, Montefalcone M, Francour P, Kulbicki M and Bianchi CN (2015) Climate change and warm-water species at the north‐western boundary of the Mediterranean Sea. Mar Ecol 36:897–909. https://doi.org/10.1111/maec.12277 Pocock MJO, Adriaens T, Bertolino S, Eschen R, Essl F, Hulme PE, Jeschke JM, Roy HE, Teixeira H, de Groot M (2024) Citizen science is a vital partnership for invasive alien species management and research. iScience 27, 108623. https://doi.org/10.1016/j.isci.2023.108623 Price-Jones V, Brown PMJ, Adriaens T, Tricarico E, Farrow RA, Cardoso AC, Gervasini E, Groom. Q, Reyserhove L, Schade S, Tsinaraki C, Marchante E (2022) Eyes on the aliens: citizen science contributes to research, policy and management of biological invasions in Europe. NeoBiota 78: 1–24. https://doi.org/10.3897/neobiota.78.81476 Pysek P, Hulme PE, Simberloff D, Bacher S, Blackburn TM, Carlton JT, Dawson W, Essl F, Foxcroft LC, Genovesi P, Jeschke JM et al (2020) Scientists’ warning on invasive alien species. Biol. Rev. 95. https://doi.org/10.1111/brv.12627 Quignard JP, Tomasini JA (2000) Mediterranean fish biodiversity. Biol Mar Medit 7 (3): 1–66. RStudio Team (2020). RStudio: Integrated Development for R. RStudio, PBC, Boston, MA URL http://www.rstudio.com/ . Rubio, M (2017) Una medusa tropical, nueva amenaza para la biodiversidad del mar Menor. https://elclickverde.com/reportajes/una-medusa-tropical-nueva-amenaza-para-la-biodiversidad-del-mar-menor (Accessed 20 September 2024). Sandahl A, Tøttrup AP (2020) Marine Citizen Science: Recent Developments and Future. Citizen Science: Theory and Practice 5(1):24. 1–11. https://doi.org/10.5334/cstp.270 Schembri PJ, Deidun A, Vella PJ (2010) First record of Cassiopea andromeda (Scyphozoa: Rhizostomeae: Cassiopeidae) from the central Mediterranean Sea. Mar Biodivers Rec 3:2. https://doi.org/10.1017/S1755267209990625 Siokou I, Ateş AS, Ayas D, Ben Souissi J, Chatterjee T, Dimiza M, Durgham H, Dogrammatzi K, Erguden D, Gerakaris V, Grego M et al. (2013) New Mediterranean Biodiversity Records (June 2013). Mediterr Mar Sci 14:238–249. https://doi.org/10.12681/mms.450 Spanier E (1989) Swarming of jellyfishes along the Mediterranean coast of Israel. Isr J Zool 36: 55–56. Stock A, Crowder LB, Halpern BS, Micheli F (2018) Uncertainty analysis and robust areas of high and low modeled human impact on the global oceans. Conservation Biol 32(6):13688–1379. https://doi.org/10.1111/cobi.13141 Stoner EW, Layman CA, Yeager LA, Hassett HM (2011) Effects of anthropogenic disturbance on the abundance and size of epibenthic jellyfish Cassiopea spp. Mar Pollut Bull 62:1109–1114. https://doi.org/10.1016/j.marpolbul.2011.03.023 Terenzini J, Li Y, Falkenberg LJ (2023) Unlocking Hong Kong’s hidden jellyfish diversity with citizen science. Regional Studies in Marine Science 62: 102896. https://doi.org/10.1016/j.rsma.2023.102896 Thé J, Mammone M, Piraino S, Pennetta A, De Benedetto GE, Garcia TM, de Oliveira Soares M, Rossi S (2023) Understanding Cassiopea andromeda (Scyphozoa) invasiveness in different habitats: a multiple biomarker comparison. Water 15:2599. https://doi.org/10.3390/w15142599 2023 Thiel M, Penna-Díaz MA, Luna-Jorquera G, Salas S, Sellanes J, Stotz W (2014) Citizen Scientist and Marine Research: Volunteer participants, their contributions, and projection for the future. Oceanogr Mar Biol: Ann Rev 52:257–314. Tiralongo F, Crocetta F, Riginella E, Lillo AO, Tondo E, Macali A, Mancini E, Russo F, Coco S, Paolillo G, Azzurro E (2020) Snapshot of rare, exotic and overlooked fish species in the Itlaian seas: A citizen science survey. Journal of Sea Research 164: 101930. https://doi.org/10.1016/j.seares.2020.101930 Tirelli V, Goruppi A, Riccamboni R, Tempesta M (2021) Citizens’ Eyes on Mnemiopsis : How to Multiply Sightings with a Click! Diversity 13:224. https://doi.org/10.3390/d13060224 Yokes MB, Andreou V, Bakiu R, Bonanomi S, Camps J, Christidis G, Crocetta F, Giovos I, Gori A, Juretic T et al. (2018) New Mediterranean Biodiversity Records (November 2018). Mediterr Mar Sci 19(3):673–89. https://doi.org/10.12681/mms.19386 Zenetos A, Gofas S, Verlaque M et al (2010) Alien species in the Mediterranean Sea by 2010. A contribution to the application of the European Union’s Marine Strategy Framework Directive (MSFD). Part I. Spatial distribution. Medit. Mar. Sci 11/2: 381–493. http://www.medit-mar-sc.net Zenetos A, Katsanevakis S, Poursanidis D, Crocetta F, Damalas D, Apostolopoulos G, Gravili C, Vardala-Theodorou E, Malaquias M (2011) Marine alien species in Greek Seas: additions and amendments by 2010. Mediterr Mar Sci 12(1):95–120 Zenetos A,Gofas S, Morri C, Rosso A, Violanti D, García Raso JE, et al (2012) Alien species in the Mediterranean Sea by 2012. A contribution to the application of the European Union’s Marine Strategy Framework Directive (MSFD). Part2. Introduction trends and pathways. Mediterr Mar Sci 13:328–352. https://doi.org/10.12681/mms.327 Zenetos A, Ovalis P, Giakoumi S, Kontadakis C, Lefkaditou E, Mpazios G, Simboura N, Tsiamis K (2020) Saronikos Gulf: a hotspot area for alien species in the Mediterranean Sea. BioInvasions Rec 9(4): 873–889. https://doi.org/10.3391/bir.2020.9.4.21 Additional Declarations No competing interests reported. Supplementary Files Supplementaryinformation.xlsx Cite Share Download PDF Status: Published Journal Publication published 30 Sep, 2025 Read the published version in Environmental Management → Version 1 posted Editorial decision: Revision requested 09 Jul, 2025 Reviews received at journal 08 Jul, 2025 Reviews received at journal 27 Jun, 2025 Reviews received at journal 24 Jun, 2025 Reviewers agreed at journal 08 Jun, 2025 Reviewers agreed at journal 04 Jun, 2025 Reviewers agreed at journal 03 Jun, 2025 Reviewers invited by journal 02 Jun, 2025 Editor assigned by journal 28 May, 2025 Submission checks completed at journal 10 May, 2025 First submitted to journal 09 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6628928","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":465639753,"identity":"0100a8eb-1352-470d-b93b-6372c0875474","order_by":0,"name":"Macarena Marambio","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0ElEQVRIiWNgGAWjYLACxgYJBn5mCJuHeC2SzSRqYWAwOECsm3Tbzz78dHOHhZzxceanGxhq6mT4G5gPf8CnxexMurF07hkJY7PDbGY3GI4d5pE4wJYmgVfLgTQG6dw2icRth3nYbjA2HOAxYOAxw+sws/PPmH+DtGxuBmupA2rh/4zfYTfS2MC2bGAGa2EG2cKA32E3nrFZg/wiAfJLAsgvQAZ+LefTmG/n7qiT4+8//OzGh5o6e/725sd4HYYKEkAEM/HqR8EoGAWjYBTgAABB/EJhErT6lQAAAABJRU5ErkJggg==","orcid":"","institution":"Institut de Ciències del Mar (ICM-CSIC)","correspondingAuthor":true,"prefix":"","firstName":"Macarena","middleName":"","lastName":"Marambio","suffix":""},{"id":465639756,"identity":"fb83dc93-abe3-4451-95b5-922fec35affd","order_by":1,"name":"Maria Pascual-Torner","email":"","orcid":"","institution":"Institut de Ciències del Mar (ICM-CSIC)","correspondingAuthor":false,"prefix":"","firstName":"Maria","middleName":"","lastName":"Pascual-Torner","suffix":""},{"id":465639762,"identity":"ef3e349f-774e-4ff4-9212-1b124623c7a6","order_by":2,"name":"Uxue Tilves","email":"","orcid":"","institution":"Institut de Ciències del Mar (ICM-CSIC)","correspondingAuthor":false,"prefix":"","firstName":"Uxue","middleName":"","lastName":"Tilves","suffix":""},{"id":465639763,"identity":"fe9f3ee9-fb20-4e48-aaf5-81d22188fda6","order_by":3,"name":"Alejandra Pérez","email":"","orcid":"","institution":"Aquatours Almería Aventuras Submarinas","correspondingAuthor":false,"prefix":"","firstName":"Alejandra","middleName":"","lastName":"Pérez","suffix":""},{"id":465639764,"identity":"71243e21-7b99-469f-a40d-63741fd8adb3","order_by":4,"name":"Ainara Ballesteros","email":"","orcid":"","institution":"IMEDMAR-UCV – Institute of Environment and Marine Science Research, Universidad Católica de Valencia SVM","correspondingAuthor":false,"prefix":"","firstName":"Ainara","middleName":"","lastName":"Ballesteros","suffix":""},{"id":465639768,"identity":"fa2d9a90-4b49-4576-94b9-578aef882ed7","order_by":5,"name":"Josep-Maria Gili","email":"","orcid":"","institution":"Institut de Ciències del Mar (ICM-CSIC)","correspondingAuthor":false,"prefix":"","firstName":"Josep-Maria","middleName":"","lastName":"Gili","suffix":""}],"badges":[],"createdAt":"2025-05-09 13:08:23","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6628928/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6628928/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00267-025-02289-w","type":"published","date":"2025-09-30T15:58:01+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":83909132,"identity":"5699227f-ee48-4ed6-a29b-bc5941e0783f","added_by":"auto","created_at":"2025-06-04 11:09:36","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":383024,"visible":true,"origin":"","legend":"\u003cp\u003eFirst records of \u003cem\u003eCassiopea andromeda\u003c/em\u003e in the Mediterranean Sea after the Suez Canal opening. \u003cstrong\u003e1\u003c/strong\u003e: Maas 1903; \u003cstrong\u003e2-3\u003c/strong\u003e: Galil et al. 1990; \u003cstrong\u003e4\u003c/strong\u003e: Çevik et al. 2006; \u003cstrong\u003e5\u003c/strong\u003e: Schembri et al. 2010; \u003cstrong\u003e6\u003c/strong\u003e: Zenetos et al. 2011; \u003cstrong\u003e7\u003c/strong\u003e: Siokou et al. 2013; \u003cstrong\u003e8\u003c/strong\u003e: Amor et al. 2015; \u003cstrong\u003e9\u003c/strong\u003e: Yokes et al. 2018; \u003cstrong\u003e10\u003c/strong\u003e: Cillari et al. 2018; \u003cstrong\u003e11\u003c/strong\u003e: Crocetta et al. 2021. The map was obtained and modified from www.d-maps.com.\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-6628928/v1/f1e9c03493cee065473b1f8a.png"},{"id":83908363,"identity":"8fcbae15-26e1-4e9a-a6c1-88b3f3037daa","added_by":"auto","created_at":"2025-06-04 11:01:36","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":687662,"visible":true,"origin":"","legend":"\u003cp\u003ea) map of Spain highlighting the coast of Almeria as the study area; b) zoom into the Marina Aguadulce study area, highlighting the sampling protocol used for individual collection. The transects (T1, T2, T3, and T4) represent the sampling paths where \u003cem\u003eC. andromeda\u003c/em\u003e individuals were found in 2023. Orange circles indicate collection sites.\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-6628928/v1/ecea332bee95ee1d795b9fe9.png"},{"id":83908359,"identity":"7e8eca41-c5f5-4d35-871d-4235ab791f67","added_by":"auto","created_at":"2025-06-04 11:01:36","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":2159528,"visible":true,"origin":"","legend":"\u003cp\u003ea) screenshot of \u003cem\u003eCassiopea \u003c/em\u003espp. Observation uploaded to \u003cem\u003eOdM\u003c/em\u003e in March 2021; b) screenshot of \u003cem\u003eCassiopea\u003c/em\u003e spp. Observation uploaded to \u003cem\u003eOdM\u003c/em\u003e in February 2023; c) screenshot of \u003cem\u003eC andromeda \u003c/em\u003eobservation uploaded to \u003cem\u003eOdM\u003c/em\u003e in December 2023; d) photographs of the population and individuals registered in the Marina Aguadulce in Andalucia in December 2023. The complete observation can be accessed at \u003ca href=\"https://www.observadoresdelmar.es/Observations/3/23385\"\u003ehttps://www.observadoresdelmar.es/Observations/3/23385\u003c/a\u003e\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-6628928/v1/36daf1b2972d2870f03496ae.png"},{"id":83909133,"identity":"eba83c69-35a6-4c32-bd82-b19cd55ad384","added_by":"auto","created_at":"2025-06-04 11:09:36","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":159560,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentation of the population’s expansion inside the Marina Aguadulce, by indicating in green the presence of individuals after 1-year monitoring.\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-6628928/v1/a55f0e9e67108c12d026239c.png"},{"id":83908360,"identity":"44d15165-2067-447d-b89d-302b0f5bbd77","added_by":"auto","created_at":"2025-06-04 11:01:36","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":106827,"visible":true,"origin":"","legend":"\u003cp\u003ePhylogenetic tree illustrating the evolutionary relationships among different \u003cem\u003eCassiopea\u003c/em\u003especies. Maximum likelihood consensus tree with bootstrap support for (left) the mitochondrial ribosomal gene 16S rRNA and (right) the mitochondrial protein-encoding gene cytochrome c oxidase I (COI) DNA. Names in bold indicate sequences generated in the present study. The gray squares group sequences that belong to the same clade species. Scale bars indicate evolutionary distance. See Table 1 for information about all the sequences used.\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-6628928/v1/0dfbd4b03b70587209bba728.png"},{"id":92883899,"identity":"dff104df-c036-4377-b46e-8d85b40397c0","added_by":"auto","created_at":"2025-10-06 16:10:36","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3960698,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6628928/v1/f0ed2921-4281-483a-a036-53b5369fa7e3.pdf"},{"id":83908362,"identity":"b5e96996-1016-4132-ab94-3dedbe8ebf52","added_by":"auto","created_at":"2025-06-04 11:01:36","extension":"xlsx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":26008,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementaryinformation.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-6628928/v1/06bea8081a9c0e570befccc9.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"The westernmost record of the scyphomedusa Cassiopea andromeda in the Mediterranean: marine citizen science contributions to invasive species detection and monitoring","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe Mediterranean Sea, listed as one of the main hotspots in the world, is home to more than 17,000 marine species, accounting for 7% of the world\u0026rsquo;s total species (Coll et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). However, this biodiversity is changing because of various human-mediated impacts, such as species introduction, direct or indirect, among others (Coll et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Stock et al. \u003cspan citationid=\"CR90\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). In particular, the presence of non-indigenous species (NIS), also called exotic, non-native, or alien species, has been used as a biodiversity loss indicator (Katsanevakis et al. \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2014\u003c/span\u003e), and invasive alien species are considered one of the major threats to marine biodiversity (Bax et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Zenetos et al. \u003cspan citationid=\"CR100\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Evans et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe Mediterranean Sea is one of the most affected seas by biological invasions (Zenetos et al. \u003cspan citationid=\"CR98\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Recent studies have listed over 950 alien species introduced into the Mediterranean (Zenetos et al. \u003cspan citationid=\"CR101\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), a fact that has been favored since the opening of the Suez Canal in 1869 (Galil \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). The Suez Canal, indeed, is the main entry point for NIS into the Mediterranean (Katsanevakis et al. \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Galil et al. \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), a phenomenon known as \u0026ldquo;lessepsian migration\u0026rdquo;. For jellyfish, scyphozoans in particular, there are records of 18 species in the Mediterranean (reviewed in Badreddine and Bitar \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), and at least 5 of them are lessepsian migrants (Galil et al. 1990, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2013\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2017\u003c/span\u003e): \u003cem\u003eRhopilema nomadica\u003c/em\u003e (Galil, Spannier and Ferguson 1990); \u003cem\u003ePhyllorhiza punctata\u003c/em\u003e (Lendenfeld, 1884); \u003cem\u003eCotylorhiza erythraea\u003c/em\u003e (Stiasny, 1920); \u003cem\u003eMarivagia stellata\u003c/em\u003e (Galil and Gershwin 2010); and \u003cem\u003eCassiopea andromeda\u003c/em\u003e (Forssk\u0026aring;l, 1775).\u003c/p\u003e \u003cp\u003e \u003cem\u003eCassiopea andromeda\u003c/em\u003e, native to the Red Sea and the Indo Pacific (Mariotini and Pane 2010), was the first lessepsian jellyfish species described after the opening of the Suez Canal. It was first sighted in Cyprus in 1903 (Mass 1903), and since then, it has been reported (at least punctually or repeatedly observed) in almost the entire eastern basin (Goy et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e1988\u003c/span\u003e; Spanier \u003cspan citationid=\"CR89\" class=\"CitationRef\"\u003e1989\u003c/span\u003e; \u0026Ccedil;evik et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Schembri et al. \u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Zenetos et al. \u003cspan citationid=\"CR99\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Siokou et al. \u003cspan citationid=\"CR88\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Yokes et al. \u003cspan citationid=\"CR97\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Crocetta et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Regarding the western basin, the presence of \u003cem\u003eC. andromeda\u003c/em\u003e has been documented on rare occasions, and the only records come from northern Tunisia (Amor et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) and Sicily (Cillari et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2018\u003c/span\u003e, Maggio et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Later, \u003cem\u003eCassiopea\u003c/em\u003e sp. was reported in Mar Menor (Murcia, Spain) in 2017 (Rubio, \u003cspan citationid=\"CR85\" class=\"CitationRef\"\u003e2017\u003c/span\u003e); however, it was an occasional grey-literature report of a single small individual without species identification.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eWithin the genus \u003cem\u003eCassiopea\u003c/em\u003e (order Rhizostomeae), which contains several species (e.g., \u003cem\u003eC. mayeri, C. frondosa, C. ornata, C. xamachana, C. andromeda\u003c/em\u003e), \u003cem\u003eC. andromeda\u003c/em\u003e is the only species reported in the Mediterranean Sea. Most reports in this area identify \u003cem\u003eC. andromeda\u003c/em\u003e by morphology without confirming it through molecular barcoding (Cillari et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Deidun et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; \u0026Ccedil;evik et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2006\u003c/span\u003e), except for that from Palermo, Sicily (Maggio et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). However, \u003cem\u003eCassiopea\u003c/em\u003e is considered a cryptic species, therefore identification based on physical characters such as the color or pattern of spots at the exumbrella, number of rhopalia, shape and number of mouth appendages, length of oral arms, or arrangement of canals in the umbrella, are not entirely reliable and rigorous, as they can be highly variable between individuals of the same species (Jarms and Morandini \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). For this reason, the use of molecular tools such as 16S ribosomal RNA (16S) and mitochondrial cytochrome c oxidase subunit I (COI) gene identity is especially relevant in any study involving this genus (Muffet et al. 2023; Holland et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2004\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cem\u003eC. andromeda\u003c/em\u003e is commonly known as the \u0026ldquo;upside down jellyfish\u0026rdquo; because it often lies on its umbrella surface to expose the symbiotic dinoflagellates of the genus \u003cem\u003eSymbiodinium\u003c/em\u003e present in their oral arms to light to facilitate photosynthesis (Lampert et al. \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). This species typically inhabits warm and well-illuminated shallow waters such as mangroves and seagrass beds and areas with muddy or sandy bottoms. Recent studies have presented records of \u003cem\u003eC. andromeda\u003c/em\u003e in harbors, such as the case of Malta (Schembri et al. \u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e2010\u003c/span\u003e) and Augusta and Palermo in Sicily (De Rinaldis et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Cillari et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2018\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe upside-down jellyfish is considered an invasive species (Katsanevakis \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2011\u003c/span\u003e), and like every invasive species, it may have an ecological impact, as it can proliferate rapidly, forming large blooms within a short time frame (Zenetos et al. \u003cspan citationid=\"CR99\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Deidun et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Additionally, it possesses certain characteristics that could facilitate its spread and establishment, particularly its high tolerance to salinity and temperature stress (Klein et al. \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), and it is able to survive at 13\u0026deg;C (Deidun et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) but also at 36\u0026deg;C (\u0026Ccedil;evik et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Moreover, increasing temperatures due to global change and high human density may enhance \u003cem\u003eCassiopea\u003c/em\u003e growth, probably because of higher nutrient availability (reviewed in Medina et al. \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). On the other hand, it may also have a socio-economic impact affecting tourism and human health as it is considered a mid-stinging species; therefore, prevention and mitigation measures must be taken where it is present, as well as the development of species-specific stinging protocols (Ballesteros et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWith the rapid expansion of NIS in the Mediterranean, the use of early detection and warning tools is essential to prevent significant ecological and/or socio-economic impacts caused by the establishment of these species in marine ecosystems. Marine citizen science, volunteers participating in marine research (Thiel et al. \u003cspan citationid=\"CR94\" class=\"CitationRef\"\u003e2014\u003c/span\u003e), is expanding and gaining great value (Earp and Liconti \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Evidence shows that it is a robust tool for providing scientific data for biodiversity conservation (McKinley et al. \u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), improving scientific monitoring at large scales (Bonney et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Dickinson et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2010\u003c/span\u003e), and contributing to research on biological invasions by acting as a tool for early detection of NIS (Delaney et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Crall et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Giovos et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Tiralongo et al. \u003cspan citationid=\"CR95\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Encarna\u0026ccedil;\u0026atilde;o et al. 2021).\u003c/p\u003e \u003cp\u003e \u003cem\u003eObservadores del Mar\u003c/em\u003e (\u003cem\u003eOdM\u003c/em\u003e; \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e\u003ca href=\"10.13039/501100011033\" target=\"_blank\"\u003ewww.observadoresdelmar.es\u003c/a\u003e\u003c/span\u003e\u003cspan address=\"http://www.observadoresdelmar.es\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e)\u003c/span\u003e, the marine citizen science platform of reference in Spain, is focused on marine conservation, answering questions to improve the understanding of marine ecosystems, and working beyond ocean health. Currently, the platform houses 15 projects addressing five relevant topics: marine biodiversity, vulnerable species, marine impacts, climate change, and exotic and invasive species. \u003cem\u003eOdM\u003c/em\u003e has managed to establish a very committed community in its 13 years of experience made up of several actors: scientific expert teams, stakeholders, collaborating organizations, the \u003cem\u003eSentinel Observatory\u003c/em\u003e network and the large community of volunteers. The \u003cem\u003eSentinel Observatory\u003c/em\u003e (\u003cem\u003eSO\u003c/em\u003e) network was created in 2016, currently comprising over 20 diving centers and clubs, associations, and other entities. The objective of this \u003cem\u003eSO\u003c/em\u003e network is to establish a more systematic data collection and monitoring by expanding even more the spatio-temporal range, therefore, acting as an early alert and becoming a functional network. The \u003cem\u003eSO\u003c/em\u003e network goes one step further in their commitment with \u003cem\u003eOdM\u003c/em\u003e by systematically monitoring one or more projects on the platform through increased sampling, project-specific dives, or research into a particular data. They report on a recurring basis and \u003cem\u003eOdM\u003c/em\u003e provides them with specific training and a more constant and dedicated exchange of information.\u003c/p\u003e \u003cp\u003e \u003cem\u003eOdM\u003c/em\u003e's commitment and dedication is not only to the \u003cem\u003eSO\u003c/em\u003e network, but to the community in general, with the aim of providing with sufficient tools to ensure the correct collection and veracity of data, to analyze and obtain results and answers to the research questions. For this reason, different materials have been developed and made available, including identification guides, a large photo database accessible to participating citizens, adapted standardized protocols, online and in-person training, as well as validation by an expert scientific team, resulting in high scientific value and an excellent-quality database (Figuerola-Ferrando et al. 2024; Coppari et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAs for jellyfish research, various initiatives have demonstrated the effectiveness of citizen science (reviewed in Marambio et al. \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), some of which provide valuable information about the ecology, spatio-temporal distribution, and the socio-economic impact in certain coastal areas (De Donno et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2014\u003c/span\u003e, Kienberger and Prieto \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2017\u003c/span\u003e, Marambio et al. \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Tirelli et al. \u003cspan citationid=\"CR96\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). In \u003cem\u003eOdM\u003c/em\u003e, one of the most successful projects is the \u0026ldquo;\u003cem\u003eJellyfish Alert\u0026rdquo;\u003c/em\u003e (Marambio et al. \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), which has been part of the platform since its creation in 2012 and currently has a very active community. The project is focused on data collection related to the presence and absence of gelatinous zooplankton organisms, including \u0026ldquo;true jellyfish\u0026rdquo; species, native and non-native, hydrozoans, ctenophores and salps. Data of one or few individuals and blooms are commonly registered, and records come mainly from the Mediterranean but also from around the world. In the years that the project has been active, a database of more than 2500 observations has been created including valuable records of the species present mainly on the Spanish coast. Recently, a protocol for monitoring climate change indicator species has been included in the project to collect data more systematically and help understand the effects of rising sea temperatures on the population and reproductive cycles of some common Mediterranean jellyfish species.\u003c/p\u003e \u003cp\u003eThis study aims to report the first phylogenetically confirmed record of the scyphomedusa \u003cem\u003eC. andromeda\u003c/em\u003e (Forsskal, 1775) in Spanish waters and the westernmost record of the species in the Mediterranean Sea, which has formed large aggregations of a self-sustained reproductive population and has remained established in the last year, even expanding its distribution in the waters of the Aguadulce Marina in Almeria, southern Spain. Furthermore, this work emphasizes the importance of marine citizen science initiatives such as \u003cem\u003eOdM\u003c/em\u003e and the involvement of its community in reporting the presence of the species, collecting samples for further scientific analyses, and monitoring the population with a temporarily systematic approach.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy area\u003c/h2\u003e \u003cp\u003eThe Marina Aguadulce is located at 36\u0026deg; 48.51\u0026rsquo; N and 2\u0026deg; 33.42\u0026rsquo; W, in the town of Roquetas de Mar, 8 km from Almer\u0026iacute;a, province of the Autonomous Community of Andalusia in Spain (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). It is mainly a touristic port with a total area of 170,462 m\u003csup\u003e2\u003c/sup\u003e and more than 750 moorings available. The sides of the different channels of the marina are formed by rocks, but the central part is made of silt (approximately 15 cm deep) and has an approximate width of 5\u0026ndash;8 m depending on the channel.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eRecord, sample collection and monitoring\u003c/h3\u003e\n\u003cp\u003eThree observations (March 2021, February 2023 and December 2023) of \u003cem\u003eCassiopea\u003c/em\u003e individuals were registered in the \u003cem\u003eJellyfish Alert\u003c/em\u003e project in the \u003cem\u003eOdM\u003c/em\u003e platform by one \u003cem\u003eSO\u003c/em\u003e of the network. The last record, from December 2023, corresponded to an aggregation of considerable abundance, therefore the expert scientific team considered it relevant to carry out a phylogenetic analysis as it is a cryptic NIS. For this purpose, twelve \u003cem\u003eCassiopea\u003c/em\u003e individuals of approximately 5 cm umbrella diameter were hand-collected by scuba divers at various locations (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) within the study area on February 11 and 12, 2024. Temperature and salinity were recorded in each sampling point. The rationale for collecting twelve individuals distributed along the Marina Aguadulce was to account for the possibility of more than one species coexisting, as other studies have detected for \u003cem\u003eCassiopea\u003c/em\u003e (Muffet et al. 2023). After collection, the specimens were preserved in 96% ethanol at room temperature and analyzed three days later.\u003c/p\u003e \u003cp\u003eMonitoring was carried out for 15 months, since the first detection in December 2023 until February 2025, and consisted of observing the presence or absence of \u003cem\u003eCassiopea\u003c/em\u003e in each of the seven channels that comprise the marina, as well as in the entrance channel, to assess its establishment and adaptation in the study area. Additionally, during the monitoring conducted in December 2023, population density was estimated in one of the seven channels (4 m wide \u0026times; 50 m long) (corresponding to T4 in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), using 1x1m quadrants. The umbrella diameter of 52 specimens was measured to estimate a rough size range.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eDNA sequencing\u003c/h3\u003e\n\u003cp\u003eDNA was extracted from each of the twelve \u003cem\u003eCassiopea\u003c/em\u003e specimens from a small portion of the umbrella margin following the standard phenol‒chloroform protocol. The quantity of DNA was assessed using Nanodrop, and its quality was checked via agarose 1% gel electrophoresis. Mitochondrial cytochrome c oxidase subunit I (COI) and 16S ribosomal RNA (16S) were amplified using primers \u0026lsquo;LCO1490-JJ2\u0026rsquo; (5\u0026prime;-CHACHACWAAYCAYAARGAYATYGG-3\u0026prime;) and \u0026lsquo;HCO2198-JJ2\u0026rsquo; (5\u0026prime;-ANACTTCNGGRTGNCCAAARAATCA-3\u0026prime;) for COI and \u0026lsquo;C\u0026amp;B1\u0026rsquo; (5\u0026prime;-TCGACTGTTTACCAAAAACATAGC-3\u0026prime;) and \u0026lsquo;C\u0026amp;B2\u0026rsquo; (5\u0026prime;-ACGGAATGAACTCAAATCATGTAAG-3\u0026prime;) for 16S, as described by Gamero-Mora et al. (\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The polymerase chain reaction (PCR) involved 5 min at 94\u0026deg;C for initial denaturation, followed by 35 cycles of amplification (denaturation at 94\u0026deg;C for 15 s, annealing at 53\u0026deg;C for 15 s and elongation at 72\u0026deg;C for 45 s) and a final extension for 5 min at 72\u0026deg;C. The PCR products were validated through 1% gel electrophoresis, purified by 1:5 dilution and Sanger sequenced at Stab Vida S. A.\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eData analysis\u003c/h2\u003e \u003cp\u003eThe 16S and COI sequences from the 12 individuals in Almeria Harbor collected in this study were aligned using the 'msa' function (from the 'msa' package) with other \u003cem\u003eCassiopea\u003c/em\u003e sequences available in the GenBank database: \u003cem\u003eC. andromeda, C. xamachana, C. mayeri, C. culionensis\u003c/em\u003e, and \u003cem\u003eC. frondosa\u003c/em\u003e, as well as with the outgroup species \u003cem\u003eMastigias papua\u003c/em\u003e and \u003cem\u003eP. punctata\u003c/em\u003e (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The alignments were trimmed to 546 bp for 16S and 514 bp for COI using 'msaTrim' (from the 'microseq' package). Phylogenetic analyses were conducted separately for 16S and COI using maximum likelihood as the optimality criterion for each. The optimal substitution model was selected via ModelFinder, choosing the model with the lowest Akaike information criterion (AIC) score: TIM2\u0026thinsp;+\u0026thinsp;F\u0026thinsp;+\u0026thinsp;I\u0026thinsp;+\u0026thinsp;G4 for 16S and TIM2\u0026thinsp;+\u0026thinsp;F\u0026thinsp;+\u0026thinsp;I for COI (Kalyaanamoorthy et al. \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Each optimal model was bootstrapped 1000 times to generate the final consensus phylogenetic tree with branch support values (Hoang et al. \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). The phylogenetic analyses were performed via IQ-TREE multicore (ver. 2.3.2). The consensus trees were visualized in Rstudio (Rstudio, \u003cspan citationid=\"CR84\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) using the 'ggtree' package, which was previously rooted in the outgroup species \u003cem\u003eM. papua\u003c/em\u003e with the 'root' function (from the 'ape' package).\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eAfter genetic analysis of the twelve collected specimens, the results revealed that they corresponded to the species \u003cem\u003eC. andromeda\u003c/em\u003e, becoming the first phylogenetically confirmed record of this species in Spain and the westernmost record of the Mediterranean basin. The observation was validated in the \u003cem\u003eJellyfish Alert\u003c/em\u003e project of the \u003cem\u003eOdM\u003c/em\u003e platform as a confirmed record of \u003cem\u003eC. andromeda\u003c/em\u003e species (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The other two previous observations, from March 2021 and February 2023, were validated only at the genus level because no phylogenetic analysis was performed.\u003c/p\u003e \u003cp\u003eDuring the sampling in February 2024, the temperature ranged from 14.2 to 14.5\u0026deg;C, and the salinity ranged from 37.5\u0026ndash;37.7. The aggregations of \u003cem\u003eC. andromeda\u003c/em\u003e were observed in various channels, mainly in the central silt area, covering the length and width of the channels at an approximate depth of 4\u0026ndash;5 m. Some of them were also observed over the meadows of another invasive species, the \u003cem\u003eRugulopteryx okamurae\u003c/em\u003e algae, which has also colonized areas of the Marina. No individuals were observed over the rocky lateral areas.\u003c/p\u003e \u003cp\u003eIndividuals were characterized by a whitish color with white and blue rounded and flattened vesicles (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). During the monitoring carried out in December 2023, the density of the population was estimated to be 80\u0026ndash;100 individuals/m\u003csup\u003e2\u003c/sup\u003e and the size of the individuals ranged from 4\u0026ndash;30 cm umbrella diameter.\u003c/p\u003e \u003cp\u003eThe monitoring conducted over 15 months indicated that the population has survived all seasons and has even expanded its distribution, having already colonized all the marina channels by 2025 (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Moreover, different stages and sizes of individuals have been observed, indicating active reproduction in the study area.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003ePhylogenetic analyses of the 12 sequences of \u003cem\u003eCassiopea\u003c/em\u003e from Almeria, Spain, combined with 24 additional sequences (most of which are available in the GenBank database), confirmed that \u003cem\u003eCassiopea\u003c/em\u003e specimens from Almeria clearly belong to \u003cem\u003eC. andromeda\u003c/em\u003e. Four COI sequences, although matching the species, showed nucleotide variations likely due to Sanger sequencing errors and were therefore excluded from the analyses to include only high-quality sequences. All specimens were clearly grouped within the clade of \u003cem\u003eC. andromeda\u003c/em\u003e, which also includes specimens from Egypt, Florida Keys, and Sicily. At the same time, the phylogenetic tree revealed the presence of other clades, such as \u003cem\u003eC. xamachana\u003c/em\u003e, which was closest to \u003cem\u003eC. andromeda\u003c/em\u003e, along with \u003cem\u003eC. culionensis, C. ornata, C. mayeri\u003c/em\u003e, and \u003cem\u003eC. frondosa\u003c/em\u003e. The bootstrap values for most nodes of the tree were greater than 80%, indicating that the consensus maximum likelihood tree was highly reliable (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSequences from Almeria were identical to the two sequences from Florida, except for one COI sequence and four 16S sequences. However, the molecular distance, measured by the Kimura 2-parameter (K80), among the sequenced individuals remained very low (0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2% for 16S and 0.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1% for COI). These values did not differ from those of \u003cem\u003eC. andromeda\u003c/em\u003e from Egypt, Florida, and Sicily (16S: 0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2% and COI: 0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3%). The intraspecific variation in \u003cem\u003eC. andromeda\u003c/em\u003e (16S: 0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2% and COI: 0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3%) was much smaller than the interspecific variation (16S: 11.2\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1 and COI: 14.3\u0026thinsp;\u0026plusmn;\u0026thinsp;6.0%). Accordingly, all these groups presented high genetic distance from the outgroup species \u003cem\u003eM. papua\u003c/em\u003e and \u003cem\u003eP. punctata\u003c/em\u003e (16S: 21.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5% and COI: 25.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9%) (Supplementary Information file).\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\u003eSequences of the mitochondrial ribosomal gene 16S rRNA and the mitochondrial protein-encoding gene cytochrome c oxidase I (COI) were used for phylogenetic analysis. Species with \u0026lsquo;*were reported as \u003cem\u003eC. frondosa\u003c/em\u003e in the sequence publication but fall into the \u003cem\u003eC. xamachana\u003c/em\u003e clade, which is supported by Muffet et al. (2023). \u0026lsquo;^\u0026rsquo; indicates that the sequences are not available in GenBank and were given by the authors. GenBank accession numbers of sequences in bold were obtained in this study\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\u003eSpecies\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLocation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16S Genbank Accession\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCOI Genbank Accession\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSource\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEl Ghardaqa, Egypt\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAY319458\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eHolland et al \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2004\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBaja California Sur, Isla San Jose, Mexico\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eKY610611\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eKY610551\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eDaglio et al. 2017\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCudjoe Key, Florida, USA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOP503932\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOP503345\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMuffet et al. 2023\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eKey Largo, Florida, USA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOP503939\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOP503367\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMuffet et al. 2023\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331484\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e-\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331485\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eCSA331497\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331486\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eCSA331498\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331487\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eCSA331499\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331488\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e-\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331489\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eCSA496001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331490\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e-\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331491\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eCSA496003\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331492\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eCSA496004\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331493\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eCSA496005\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331494\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e-\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAlmer\u0026iacute;a, Spain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eCSA331495\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eCSA496007\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis study\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePalermo, Sicily\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCa2_CaCOIF^\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMaggio et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2019\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePalermo, Sicily\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCa1_CaCOIF^\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMaggio et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2019\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea andromeda\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePalermo, Sicily\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCa4_CaCOIF^\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMaggio et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2019\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea culionensis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLapu-Lapu, City of Cebu, Philippines\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMW164869\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMW160913\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGamero-Mora et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea culionensis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLapu-Lapu, City of Cebu, Philippines\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMW164879\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMW160923\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGamero-Mora et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea culionensis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLapu-Lapu, City of Cebu, Philippines\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMW164886\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMW160930\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGamero-Mora et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea frondosa\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWest Key, Florida, USA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eKY610617\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAY319467\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eHolland et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2004\u003c/span\u003e and Daglio et al. 2017\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea mayeri\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRyukyu Islands, Okinawa, Japan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMW164859\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMW160931\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGamero-Mora et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea mayeri\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLapu-Lapu, City of Cebu, Philippines\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMW164863\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMW160934\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGamero-Mora et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea mayeri\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLapu-Lapu, City of Cebu, Philippines\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMW164864\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMW160935\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGamero-Mora et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea mayeri\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCalatagan, Luzon Island, Philippines\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMW164865\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMW160936\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGamero-Mora et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea mayeri\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCalatagan, Luzon Island, Philippines\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMW164866\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMW160937\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGamero-Mora et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea ornata\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eKakaban, Kalimantan, Indonesia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAB720918\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAY319472\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eHolland et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2004\u003c/span\u003e and Gamero-Mora 2022\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea ornata\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGuam, USA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOL721669\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOL799293\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAnthony et al. 2022\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea xamacana*\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBahia Delfines, Bocas del Toro, Panama\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eKY610613\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eKY610558\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eG\u0026oacute;mez Daglio and Dawson \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2017\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea xamacana*\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBahia Delfines, Bocas del Toro, Panama\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eKY610614\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eKY610559\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eG\u0026oacute;mez Daglio and Dawson \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2017\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea xamachana\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTavernier, Florida, USA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOP503922\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOP503334\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMuffet et al. 2023\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCassiopea xamachana\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLobster Walk, Monroe County,Florida, USA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOP503929\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOP503341\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMuffet et al. 2023\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eMastigias papua\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRisong Cove, Palau\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eKU901021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eKU901397\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSwift et al 2016\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003ePhyllorhiza punctata\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGulf of California, Mexico\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMT902932\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMT904380\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRosales-Catal\u0026aacute;n et al 2021\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eAccording to Zenetos et al. (\u003cspan citationid=\"CR101\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), almost 1000 marine NIS have been introduced into the Mediterranean. Although the number of alien species in the Mediterranean varies between regions (Zenetos et al. \u003cspan citationid=\"CR100\" class=\"CitationRef\"\u003e2012\u003c/span\u003e), the majority occur in the Eastern sub-region. The Sicily Channel plays an important role in this distribution pattern since it has been traditionally considered a biogeographical barrier that prevents the spread of these species, restricting them to the eastern basin (e.g., Quignard and Tommasini 2000). Nevertheless, some species have crossed the Sicily channel and have been found in the western region. This is the case for some lessepsian scyphomedusae species, such as our target species \u003cem\u003eC. andromeda\u003c/em\u003e (Morandini et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Aljbour et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Medina et al. \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), and others, such as \u003cem\u003eR. nomadica\u003c/em\u003e (Balistreri et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2017\u003c/span\u003e)d \u003cem\u003epunctata\u003c/em\u003e (Deidun et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cem\u003eC. andromeda\u003c/em\u003e is one of the 18 species of jellyfish reported as NIS in the Mediterranean. Its records, although not all phylogenetically confirmed, are diverse. Until now, the species had not been confirmed in Mediterranean Spanish waters, and its westernmost record was from Italy (Maggio et al \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). In this work, we report the first phylogenetically confirmed record of the NIS \u003cem\u003eC. andromeda\u003c/em\u003e in Spanish waters and the westernmost record of this species in the Mediterranean Sea. The analysis suggests that the population in this location consists solely of \u003cem\u003eC. andromeda\u003c/em\u003e (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e), excluding any coexistence with \u003cem\u003eC. xamachana\u003c/em\u003e, as described in other studies (Muffet et al. 2023). Overall, the bootstrap values (an indicator of the confidence in the placement of a particular clade within a phylogenetic tree) were between 80% and 99%, with few values lower than 70%, in accordance with other phylogenetic studies of \u003cem\u003eCassiopea\u003c/em\u003e species (Muffet et al. 2023, Gamero-Mora et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e, Arai et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). When comparing the COI and 16S trees, the former had higher bootstrap values, except for the node between the clades \u003cem\u003eC. ornata/C. culionensis\u003c/em\u003e and \u003cem\u003eC. mayeri\u003c/em\u003e (63%). However, the bootstrap value of the analogous node in the 16S tree was greater (81%). Therefore, the phylogenetic results in this study are highly reliable.\u003c/p\u003e \u003cp\u003eThe phylogenetic tree, which uses either 16S or COI markers, indicates that each \u003cem\u003eCassiopea\u003c/em\u003e species diverged through distinct evolutionary paths, in accordance with other phylogenetic studies of \u003cem\u003eCassiopea\u003c/em\u003e (Gamero-Mora et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Muffet et al. 2023). These trees show that \u003cem\u003eC. frondosa\u003c/em\u003e is distinct from the other species, indicating early divergence. Interestingly, this is the only \u003cem\u003eCassiopea\u003c/em\u003e species that can be unequivocally identified by morphology (it has a different number of rhopalia) (Morandini et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Later in evolution, there was a divergence into two distinct clades: the \u0026ldquo;\u003cem\u003eC. andromeda/C. xamachana\u003c/em\u003e'' and \u0026ldquo;\u003cem\u003eC. mayeri/C. ornata/C. culionensis\u003c/em\u003e\u0026rdquo; clades, where \u003cem\u003eC. mayeri\u003c/em\u003e diverged from the latter. Finally, \u003cem\u003eC. andromeda\u003c/em\u003e-\u003cem\u003eC. xamachana\u003c/em\u003e, and \u003cem\u003eC. ornata\u003c/em\u003e-\u003cem\u003eC. culionensis\u003c/em\u003e diverged from their most recent common ancestors, indicating recent evolution, and suggesting potential cryptic species within these groups (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eCrypticity is common in Scyphozoa and can lead to species misidentification when it is detected only by morphology (Moura et al. \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Holland et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Dawson et al. 2003). In the context of invasive species, crypticity complicates their detection and management, hampering the prediction and control of their impacts (Jarić et al. \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). In that sense, when a species has been sighted in a new location, barcoding identification\u0026mdash;alone or combined with morphological description\u0026mdash;is indispensable to ensure correct identification and management. There is a large difference between naming a study species and labeling it with DNA barcodes (such as 16S or COI markers), with the latter being much more precise. In addition, if the generated DNA barcodes are stored in public databases, they may be available for future phylogenetic studies. For example, our phylogenetic tree revealed that \u003cem\u003eCassiopea\u003c/em\u003e from Panama, which Gomez Daglio and Dawson (2017) identified as \u003cem\u003eC. frondosa\u003c/em\u003e, corresponds to \u003cem\u003eC. xamachana\u003c/em\u003e, which is in accordance with the findings of Muffet et al. (2023). This fact, together with other examples of reidentification of \u003cem\u003eCassiopea\u003c/em\u003e species (Gamero-Mora et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), highlights how DNA barcoding allows species identification to be adapted in future studies, considering that taxonomy can change over time.\u003c/p\u003e \u003cp\u003eThe introduction pathway of \u003cem\u003eC. andromeda\u003c/em\u003e into Spanish waters is unknown. As an epibenthic scyphozoan, this jellyfish has a very limited swimming capability, and most of the translocations reported in this species are more likely to be related to maritime transportation rather than natural transport by currents or by its own displacement (Holland et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Schembri et al. \u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). We hypothesize that \u003cem\u003eC. andromeda\u003c/em\u003e from this study, possibly the polyp stage, could have arrived by vessel transportation and probably as biofouling, since the study area is a marina and does not have ballast water loads. This hypothesis agrees with the case of Turkey, where the authors also suggested that polyps may have arrived in ships as biofouling (\u0026Ccedil;evik et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2006\u003c/span\u003e) while the pelagic stages in ballast water (\u0026Ouml;zg\u0026uuml;r and \u0026Ouml;zt\u0026uuml;rk \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Additionally, in Malta, the authors indicated the possibility that recreational vessels could be the vector for the introduction of this species (Deidun et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). In any case, independent of the arrival pathway, the current environmental conditions in the study area are certainly suitable for the species to develop and establish large populations, as has been observed in the last year after its first detection. The presence of this species in harbors and marinas has also been described in other areas, such as Malta, Sicily and Turkey (Schembri et al. \u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Cillari et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; \u0026Ccedil;ardak et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2011\u003c/span\u003e, respectively). Harbors have been described as an ideal region for NIS introduction because of high maritime traffic (Ferrario et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) and, in the case of \u003cem\u003eC. andromeda\u003c/em\u003e, it has been demonstrated that human-impacted coastal habitats may enhance its ability to sustain populations and contribute to its establishment (\u0026Ccedil;evik et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Th\u0026eacute; et al. \u003cspan citationid=\"CR93\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Stoner et al. \u003cspan citationid=\"CR91\" class=\"CitationRef\"\u003e2011\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFollowing the history of invasive species in the Mediterranean, several authors have suggested that finding lessepsian species in the western basin may be considered an indicator of the warming trend of the Mediterranean Sea (Boero et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Daly Yahia et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Water warming facilitates the natural spread of tropical and subtropical species, enabling them to expand their distribution range (Lasram et al. \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Parravicini et al. \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). In this context, the Mediterranean Sea stands out as one of the most significant and susceptible regions to climate change (Giorgi \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Lionello et al. \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e2012\u003c/span\u003e), experiencing a warming rate per decade that exceeds the global average by more than threefold. These climate change conditions, and the resulting increase in sea temperature, may support the distribution and establishment of thermophilic species such as \u003cem\u003eC. andromeda\u003c/em\u003e (\u0026Ccedil;evik et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2006\u003c/span\u003e), which is considered to enhance its physiological response to global warming (Aljbour et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2017\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Banha et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), and whose thermal tolerance could promote an increase in the population and expansion of its geographic distribution range (Aljbour et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cem\u003eC. andromeda\u003c/em\u003e records in the Mediterranean are from semi-enclosed eutrophic shallow waters with low hydrodynamics (Maggio et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). This is the case for the harbors mentioned above and for nature reserves (Malta, Deidun et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), marine protected areas (Tunisia, Amor et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), the cooling water drainage channel of a factory (Turkey, \u0026Ccedil;evik et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2006\u003c/span\u003e) or lagoons (Turkey, \u0026Ouml;zg\u0026uuml;r and \u0026Ouml;zt\u0026uuml;rk \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). These shallow areas, although quite stressful (e.g., high temperatures/irradiation and potential extreme salinity changes), have been demonstrated to be suitable for their establishment, probably because of the high tolerance of this jellyfish to environmental variation (Morandini et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Mammone et al. \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). In previous works, it has been described at different temperatures ranging from 14.1\u0026ndash;17.6\u0026deg;C in Palermo (Maggio et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), 13.36\u0026ndash;14.49\u0026deg;C in Malta (Deidun et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), and 29\u0026ndash;36\u0026deg;C in Turkey (\u0026Ccedil;evik et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; \u0026Ouml;zg\u0026uuml;r and \u0026Ouml;zt\u0026uuml;rk \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). In this study, \u003cem\u003eC. andromeda\u003c/em\u003e was first detected in winter (December‒February) when the water temperature was ~\u0026thinsp;14.2\u0026deg;C and has been monitored and observed throughout the year following the yearly temperature range. The high abundances (80‒100 individuals/m\u003csup\u003e2\u003c/sup\u003e) recorded in the present study, are much higher compared with other studies where the maximum abundances described were 30‒40 individuals/m\u003csup\u003e2\u003c/sup\u003e (Niggl and Wild \u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e2010\u003c/span\u003e), especially considering that it is very likely that the density is underestimated since according to the information reported by the \u003cem\u003eSO\u003c/em\u003e during the monitoring reporting, the jellyfish were one on top of the other forming layers that did not allow counting all the individuals in each quadrant.\u003c/p\u003e \u003cp\u003eMarine citizen science, as a growing opportunity for marine research (Sandahl and Tottrup 2020; Earp and Liconti \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Changeux et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Garc\u0026iacute;a-Soto et al. \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), has been reported in previous studies (Johansen et al. \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Marambio et al. \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Tirelli et al. \u003cspan citationid=\"CR96\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Edelist et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Dobson et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Terenzini et al. \u003cspan citationid=\"CR92\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) as a highly valuable tool for increasing knowledge about jellyfish distribution. Additionally, it provides essential data for establishing and/or improving preventive programs to mitigate jellyfish impacts in some coastal areas. In recent years, another growing area of ​​citizen science is the reporting of NIS, therefore considered a useful tool for expanding the scale of data collection, for early detection and for monitoring exotic and invasive species (Delaney et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Crall et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Mannino and Balistreri \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Giovos et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Tiralongo et al. \u003cspan citationid=\"CR95\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Pocock et al. \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). All this represents a clear benefit in expanding exotic and invasive species knowledge, and in their monitoring, management, and related policy development (Groom et al. \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Pysek et al. \u003cspan citationid=\"CR82\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Price-Jones et al. \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eDetecting NIS as early as possible, along with monitoring and research, is essential for determining the ecological and socio-economic impacts that their presence and establishment could have on invaded areas (Giovos et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Pocock et al. \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). In these instances, marine citizen science requires significant involvement from volunteers, as participation goes beyond mere observation reporting. Therefore, it is essential that platforms and initiatives have a track record and are well established, with strong community engagement. In this sense, \u003cem\u003eOdM\u003c/em\u003e has a large and highly engaged community of volunteers from different sectors and a robust network of Sentinel Observatories (\u003cem\u003eSO\u003c/em\u003e). Aquatours Almeria, the diving center that reported the presence of \u003cem\u003eC. andromeda\u003c/em\u003e, has been part of this SO network since the beginning. In fact, 75% of the \u003cem\u003eSO\u003c/em\u003e network consists of diving centers or clubs, which represents a good opportunity for marine citizen science, as divers are considered one of the most committed user groups, according to previous studies (Martin et al. \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2016\u003c/span\u003e, Lucrezi et al. \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Moreover, \u003cem\u003eOdM\u003c/em\u003e has demonstrated its consistency in effectively contributing to the early detection of NIS, expanding knowledge, and contributing to decision-making related to marine conservation (Azzurro et al. 2013, 2020; Castej\u0026oacute;n-Silvo et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Figuerola-Ferrando et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe \u003cem\u003eOdM\u003c/em\u003e platform, through its specific project \u0026ldquo;Jellyfish Alert\u0026rdquo;, provides the necessary identification clues and expert support to recognize jellyfish species easily under good conditions. However, in some cases phylogenetic analysis is required for a correct identification, especially for cryptic species such as \u003cem\u003eCassiopea\u003c/em\u003e individuals. When further analysis is needed, the close collaboration with the \u003cem\u003eOdM\u003c/em\u003e\u0026rsquo;s \u003cem\u003eSO\u003c/em\u003eenables the collection of samples as they immediately receive a protocol from the scientific team with instructions for sample collection, ultimately allowing for species confirmation. Furthermore, as a \u003cem\u003eSO\u003c/em\u003e of the platform's network, they regularly conduct structured monitoring at the same location during their year-round dives. This has allowed them to track the species for more than 12 months since its detection, and they have been able to observe and report on its reproduction and expansion in the colonized area. This will allow us to get valuable information to assess the impact of the species over time (Pocock et al. \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Moreover, with this confirmed record, the message can be expanded to the public and encourage attention to this species. It will also contribute to understanding the importance and impact of invasive species on marine ecosystems and contribute to adaptive management strategies within a citizen science approach (Giovos et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Pocock et al. \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe detection of NIS is highly relevant to the ecology of ecosystems and the conservation of the marine environment. The case of \u003cem\u003eC. andromeda\u003c/em\u003e is of particular interest because it can be easily transported as biofouling and/or ballast water, and when it arrives in a new area, it can easily adapt to different environmental conditions, being highly thermotolerant. These characteristics, together with rising sea temperatures due to climate change, make almost any point in the Mediterranean a suitable place for this species, which, in addition, can spread rapidly, affecting local populations. This study contributes to the knowledge of the NIS \u003cem\u003eC. andromeda\u003c/em\u003e in the Mediterranean, presenting the first phylogenetically confirmed record in Spanish waters and the westernmost record in the basin, as well as the contribution to public DNA databases. On the other hand, marine citizen science has proven useful and, if well implemented, is a powerful tool that allows the expansion of spatial-temporal marine research, improves ecological understanding, and contributes to ocean literacy-enhancing knowledge. In the case of NIS, it has an important value as a detection tool that has been used in various taxonomic groups, including jellyfish. For instance, the present study demonstrates the relevance of the marine citizen science platform \u003cem\u003eOdM\u003c/em\u003e, as it plays a fundamental role in the detection, sampling and monitoring of this species through its engaged community. The potential of marine citizen science in reporting the presence of certain species and acting as a warning tool is unquestionable, as the advantage of having a large and engaged community makes it a highly cost-effective tool. This collaboration between scientists and citizens is translated into advances in marine research, management and even policy. With more than 12 years of experience, \u003cem\u003eOdM\u003c/em\u003e has demonstrated the commitment of its community, the importance of providing training and standardized protocols, and the quality of the data. Furthermore, it implements all the recommendations for the establishment and successful development of a marine citizen science platform, and its contributions thus far confirm its success.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study has been supported by the LIFE IP Intemares project (LIFE15 IPE/ES/012) and the OdM Climate project supported by the Biodiversity Foundation of the Spanish Ministry for Ecological Transition and the Demographic Challenge, through the Call for projects that contribute to the implementation of the National Plan for Adaptation to Climate Change (2021-2030), and the PID2020-118394RB-100 project. All the authors affiliated to the Institut de Ciències del Mar (ICM-CSIC) acknowledge the support of the “Severo Ochoa Centre of Excellence\" accreditation (\u003cem\u003eCEX2024-001494-S\u0026nbsp;funded by AEI 10.13039/501100011033\u003c/em\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests:\u0026nbsp;\u003c/strong\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest:\u003c/strong\u003e The authors declare no potential conflict of interest in the present work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials:\u0026nbsp;\u003c/strong\u003eDNA sequences were submitted to GenBank\u0026nbsp;(accession numbers: PQ154578–PQ154589 for 16S sequences and PV533755–PV533762 for COI sequences).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStudy Conceptualization and Investigation were performed by Macarena Marambio, Maria Pascual-Torner and Uxue Tilves. Data collection and Formal Analysis were performed by Macarena Marambio, Maria Pascual-Torner and Alejandra Perez. Writing of the original draft was performed by Macarena Marambio, Maria Pascual-Torner, Uxue Tilves. Review and editing of the manuscript were performed by Macarena Marambio, Maria Pascual-Torner, Uxue Tilves, Josep Maria Gili, Alejandra Perez and Ainara Ballesteros. Supervision of the study was performed by Macarena Marambio, Maria Pascual-Torner and Josep Maria Gili. All authors read and approved the final manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to thank all the citizen scientists involved in Observadores del Mar, as well as all the\u0026nbsp;Sentinel Observatories of the platform, specially to Aquatours Almeria Aventuras Submarinas and all their staff for their implication and proactive attitude toward the sampling, monitoring and the research. We also thank Jose Maria Perez Freije from the University of Oviedo for his support on the genetic analysis.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAljbour SM, Zimmer M, Kunzman A (2017) Cellular respiration, oxygen consumption, and trade-offs of the jellyfish \u003cem\u003eCassiopea\u003c/em\u003e sp. In response to temperature change. J Sea Res 128: 92\u0026ndash;97. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.1016/j.seares.2017.08.006\u003c/span\u003e\u003cspan address=\"10.1016/j.seares.2017.08.006\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAljbour SM, Zimmer M, Al-Horani FA, Kunzman A (2019) Metabolic and oxidative stress responses of the jellyfish \u003cem\u003eCassiopea\u003c/em\u003e sp. To changes in seawater temperature. 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BioInvasions Rec 9(4): 873\u0026ndash;889. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3391/bir.2020.9.4.21\u003c/span\u003e\u003cspan address=\"10.3391/bir.2020.9.4.21\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"environmental-management","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"emvm","sideBox":"Learn more about [Environmental Management](http://link.springer.com/journal/267)","snPcode":"267","submissionUrl":"https://submission.nature.com/new-submission/267/3","title":"Environmental Management","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"NIS, Lessepsian invasion, climate change, geographical spread, participatory science, thermophilic jellyfish.","lastPublishedDoi":"10.21203/rs.3.rs-6628928/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6628928/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe Mediterranean Sea, although a biodiversity hotspot, is one of the most affected seas by non-indigenous species (NIS). This problem is worsened by rising sea temperatures due to climate change, which promotes the spread of thermophilic species. Among the NIS scyphozoan jellyfish species recorded in the Mediterranean, \u003cem\u003eCassiopea andromeda\u003c/em\u003e \u0026ndash; commonly known as the \"upside-down jellyfish\"\u0026ndash; is a notable example. \u003cem\u003eObservadores del Mar\u003c/em\u003e (\u003cem\u003eOdM\u003c/em\u003e) is the leading platform for marine citizen science in Spain and works towards ocean conservation and health. It is a well-established tool for generating knowledge in marine research and has successfully provided early warning of NIS reports in the Mediterranean, while also serving as an effective network for the monitoring of NIS and other indicators. Three reports of \u003cem\u003eC. andromeda\u003c/em\u003e from Almeria, southern Spain have been reported in \u003cem\u003eOdM\u003c/em\u003e and thanks to the involvement of its community, 12 samples were collected for phylogenetic analysis and monitoring was done for 15 months in the study area. The results confirmed the first record of \u003cem\u003eC. andromeda\u003c/em\u003e in Spanish Mediterranean waters representing the westernmost record in the basin. Monitoring also suggest the species establishment in the area. This study contributes to the knowledge of \u003cem\u003eC. andromeda\u003c/em\u003e invasiveness and highlights the importance of marine citizen science in the detection and monitoring of NIS. It also underscores the collaboration and commitment already established between scientists and citizens, which will allow further progress in the fields of biological invasions, management, and policy.\u003c/p\u003e","manuscriptTitle":"The westernmost record of the scyphomedusa Cassiopea andromeda in the Mediterranean: marine citizen science contributions to invasive species detection and monitoring","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-04 11:01:31","doi":"10.21203/rs.3.rs-6628928/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-10T00:14:37+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-08T16:09:37+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-27T07:53:28+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-24T19:59:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"52844745005990203137379991419275590460","date":"2025-06-08T06:15:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"149912582391620196379189973635382689494","date":"2025-06-05T00:00:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"5495023528915008405569340630597184820","date":"2025-06-03T06:03:35+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-02T04:06:30+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-28T04:22:27+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-10T14:12:20+00:00","index":"","fulltext":""},{"type":"submitted","content":"Environmental Management","date":"2025-05-09T13:02:20+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"environmental-management","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"emvm","sideBox":"Learn more about [Environmental Management](http://link.springer.com/journal/267)","snPcode":"267","submissionUrl":"https://submission.nature.com/new-submission/267/3","title":"Environmental Management","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"c040956c-f6ce-49b8-bc44-ddeb45670843","owner":[],"postedDate":"June 4th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-10-06T16:04:20+00:00","versionOfRecord":{"articleIdentity":"rs-6628928","link":"https://doi.org/10.1007/s00267-025-02289-w","journal":{"identity":"environmental-management","isVorOnly":false,"title":"Environmental Management"},"publishedOn":"2025-09-30 15:58:01","publishedOnDateReadable":"September 30th, 2025"},"versionCreatedAt":"2025-06-04 11:01:31","video":"","vorDoi":"10.1007/s00267-025-02289-w","vorDoiUrl":"https://doi.org/10.1007/s00267-025-02289-w","workflowStages":[]},"version":"v1","identity":"rs-6628928","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6628928","identity":"rs-6628928","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}