Viral metagenomics reveals persistent as well as dietary acquired viruses in Antarctic fur seals.

Viruses linked to animals inhabiting Antarctic latitudes remain poorly studied. Remote environments hosting large pinniped populations may be prone to exposure of immunologically naïve animals to new infectious agents due to increasing human presence or introduction of new animal species. Antarctic fur seals (Arctocephalus gazella) inhabiting the Western Antarctic Peninsula and the South Shetland Islands are challenged because of climate change and increased anthropogenic activity. In the present study, the fecal and serum virome of A. gazella was characterized by applying target enrichment next generation sequencing. The resulting viromes were dominated by CRESS-DNA sequences. Viruses known to infect vertebrate and invertebrate hosts were also observed in fecal samples. Fur seal picornavirus was present in all the fecal pools studied suggesting it is a prevalent virus in these species. Six different viruses presenting similarities with previously described A. gazella viruses or other otariids and mammal viruses were identified as potential new A. gazella viruses. Also, diet-derived viruses such as crustacean viruses were present in fecal content. Penguin viruses, but not fish viruses, were also detected. Obtained results contribute to a better understanding of the viral community present in these species, which is relevant for its conservation

Niche partitioning amongst northwestern Mediterranean cetaceans using stable isotopes

Ten species of cetaceans coexist in the Mediterranean Sea, one of the richest seas in biodiversity and endemisms worldwide. The conservation status of Mediterranean cetaceans has been a concern for many years, particularly due to increasing anthropogenic threats such as global warming and overfishing. We established the stable isotopic niches of carbon, nitrogen, and sulphur for five species of cetaceans inhabiting the northwestern Mediterranean Sea to elucidate the mechanisms of coexistence. The fin whale exploited epipelagic habitats with a low trophic level; the bottlenose dolphin was mostly neritic and had a high trophic level; the Risso's dolphin was oceanic and fed bathypelagically and at a high trophic level; finally, the common and striped dolphins displayed epipelagic distributions and similarly intermediate trophic levels. The isotopic niches of all species were exclusive except the common and striped dolphins, whose niches overlapped by 25%. These results suggest that the majority of species avoid competitive exclusion by trophic or spatial segregation with the exception of striped and common dolphins, in which interspecific competition is apparent. It is suggested that this competition brought the striped dolphin to displace the common dolphin from part of its distribution range, restricting it to the southern fringe of the western Mediterranean and, particularly, to the Alboran Sea. In this area, coexistence of the two species would be permitted by some degree of spatial segregation between them and a remarkably high productivity, all which mitigate competition

Perfluoroalkyl substances in striped dolphins (Stenella coeruleoalba) from the NW Mediterranean Sea: Biomagnification and temporal trends (1990-2021)

Poly- and Perfluoroalkyl Substances (PFAS) are widely recognized as a class of pollutants known for their ability to bioaccumulate and biomagnify in the environment. In this study, the objective is to determine the biomagnification rates of PFAS in sexually mature striped dolphins and assess the temporal trends of PFAS concentrations over the past three decades (1990-2021) in the North-Western Mediterranean Sea. Thirteen out of the 19 targeted PFAS compounds were detected in the digestive content of the dolphins, while all 17 PFAS compounds were detected in the liver samples. Concentrations of PFAS in the digestive content ranged from 50 to 1611 ng/g, while the liver samples showed concentrations ranging from 268 to 7014 ng/g. The most prevalent compounds found in both types of samples were linear perfluorooctanesulfonic acid (n-PFOS) and perfluorooctanesulfonamide (FOSA), which were present in all samples. Additionally, perfluoroundecanoic acid (PFUnDA), perfluorotridecanoic acid (PFTrDA), and perfluorononanoic acid (PFNA) were also detected in significant quantities. Interestingly, the study found that long-chain PFAS compounds exhibited greater biomagnification rates compared to short-chain PFAS compounds in striped dolphins. This suggests a potential impact on the health of these marine mammals due to the accumulation of long-chain PFAS in their systems. The analysis of the samples indicated that half of the digestive content samples exceeded the Environmental Quality Standards (EQS) concentrations, indicating that the consumption of polluted prey may pose health risks for striped dolphins. When examining the temporal trends, the concentrations of most long-chain PFAS compounds showed an increase from 1990 to 2004-2009. However, concentrations appeared to stabilize during the period of 2014-2021, potentially reflecting the impact of country regulations and industry initiatives aimed at reducing PFAS pollution. These findings underscore the persistent presence of banned PFAS compounds in the marine ecosystem and highlight the need for ecological risk assessments and the development of management strategies to mitigate PFAS pollution in marine environments. In conclusion, this study provides valuable insights into the biomagnification rates of PFAS in striped dolphins and highlights the persistent nature of these pollutants in the North-Western Mediterranean Sea. The identification of specific PFAS compounds and their temporal trends contribute to the understanding of PFAS pollution and support future efforts in assessing ecological risks and implementing effective management strategies in marine ecosystems

Mediterranean Sea Literacy: When Ocean Literacy becomes region-specific

Ocean Literacy (OL) has been defined as an understanding of the ocean’s influence on people and their influence on the ocean. The OL movement was born in the US and its framework consisted of seven essential principles and 45 fundamental concepts; it is now largely accepted worldwide for use in both formal (schools and universities) and non-formal (research institutes, aquaria, museums, etc.) education settings. Based on this framework, marine scientists and educators developed the “Mediterranean Sea Literacy” (MSL) guide adapted to the specificities of the Mediterranean region, presented here. The MSL principles (7) and concepts (43), serving as guidance for research, education, informed decision-making, and improved citizens’ lifestyles, aim to contribute to environmental protection, conservation, and restoration of the Mediterranean Sea as well as to help to achieve a blue innovative and sustainable economy

Assessing the current status of Hexanchus griseus in the Mediterranean Sea using local ecological knowledge

Fishermen from 9 countries distributed throughout the Mediterranean Sea were interviewed between May and December 2019 with the aim of compiling information about the current impact of fisheries on a large deepwatershark species, the bluntnose sixgill shark (Hexanchus griseus). A total of 382 professional fishermenbelonging to 6 different gears (bottom trawling, bottom longline, drifting longline, trammel nets, gillnets andpolyvalent) took part in the study. Bottom trawlers were the most interviewed fishermen (n = 148) and the bestfleet coverage was obtained for bottom longline (38.89%). Results showed most captures of H. griseus occur in theWestern and Central Mediterranean Sea, particularly during the warm months of the year and most commonly bybottom trawlers and bottom longliners. At-vessel mortality (AVM) was rather low in all gears but a slightlyhigher degree of individual mortality is suggested in trammel and gillnets. The population trend of H. griseus inthe Mediterranean Sea could not be inferred from the interviews as answers were highly variable, but the overalltrend in some countries may suggest this species is showing signs of population decrease. The results of this studyare mostly aligned with the latest IUCN assessment but also recommend reviewing the current status of H. griseusin the Mediterranean basin. Further empirical research on post-release mortality would also be advisable toimplement measures that help reduce this source of mortality

The Seabed Makes the Dolphins: Physiographic Features Shape the Size and Structure of the Bottlenose Dolphin Geographical Units

The common bottlenose dolphin (Tursiops truncatus) is a cosmopolitan delphinid, regularly present in the Mediterranean Sea. According to previous studies, this dolphin tends to form resident geographical units scattered on the continental shelf. We investigated how the physiographic characteristics of the area of residence, with special reference to the size and shape of the continental shelf, affect the home range and the group size of the local units. We analysed and compared data collected between 2004-2016 by 15 research groups operating in different study areas of the Mediterranean Sea: the Alboran Sea, in the South-Western Mediterranean, the Gulf of Lion and the Pelagos Sanctuary for the marine mammals, in the North-Western Mediterranean, and the Gulf of Ambracia, in the North-Central Mediterranean Sea. We have found that in areas characterised by a wide continental platform, dolphins have wider home ranges and aggregate into larger groups. In areas characterized by a narrow continental platform, dolphins show much smaller home ranges and aggregate into smaller groups. The results obtained from this collective research effort highlight the importance of data sharing to improve our scientific knowledge in the field of cetaceans and beyond

Cephalopods in the diet of Risso's dolphin (Grampus griseus ) from the Mediterranean Sea: a review

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThe Risso's dolphin, Grampus griseus, is a deep-sea cetacean with a predominantly teuthophagous diet. Its distribution in the northwest Mediterranean is generally in deeper waters, but there is little information on diet or feeding areas. To extend knowledge of the diet of G. griseus, the stomach contents of six stranded Risso's dolphins in the Mediterranean Sea were analyzed. A total of 578 cephalopod beaks (166 uppers and 392 lowers) were found, identified as 386 individuals from 19 different species of Coleoidea cephalopods, one Sepiolida, eight Octopoda, and ten species belonging to the Order Oegopsida. This adds six species of cephalopods to those previously recorded in the Mediterranean Sea: Rondeletiola minor, Eledone moschata, Scaeurgus unicirrhus, Bathypolypus sponsalis, Pteroctopus tetracirrhus and Taonius pavo. In this study the most abundant prey family was Histioteuthidae. In addition, based on the available literature, the diet of 39 Risso's dolphins was reviewed in Mediterranean waters. The abundance of cephalopod species in the diet of these specimens was compared according to genus, geographical area, season, and age. The habitat of the prey of G. griseus was reviewed, suggesting a teuthophagous diet in this area. This study helps to identify both the prey species and the areas where prey are available in the northwest Mediterranean, which are key factors in establishing the limits and regulations of the “Northwest Mediterranean Sea, Slope and Canyon IMMA System” (Important Areas for Marine Mammals) proposed by the Working Group on Marine Mammal Protected Areas (MMPATF - IUCN)

Moult in the Mediterranean monk seal from Cap Blanc, western Sahara

At birth, the Mediterranean monk seal (Monachus monachus) is covered with dark lanugo. This is shed earlier and faster in females, so they complete the moult when they are significantly younger (64 days) than males (82 days). Moulted pups  present a greyish dorsal and a white ventral pelage. Only the hair is shed in the first moult. In subsequent moults, the hairs are shed along with large sheets of cornified epidermis. A series of sequential stages were identified, which included a long  pre-moult phase (brown pelage) and a post-moult phase (dull appearance). The  shedding process lasted 15 days. It is different to that of the Hawaiian monk seal and elephant seals, as Mediterranean monk seals partly moult in the water. The  intermoult period was close to  one year except in females nursing a pup. Such females have longer intermoult periods and can even moult whilst still lactating. In males, the process of developing the mature pelage pattern of bulls is gradual. It involves at least two annual moults and can be completed by the age of 4 years.Key words: Mediterranean monk seal, Monachus, moult, lanugo, shedding, pelage

Cephalopods in the diet of Risso's dolphin (Grampus griseus) from the Mediterranean Sea: A review

17 pages, 6 figures, 2 tables, supporting information https://doi.org/10.1111/mms.12869The Risso's dolphin, Grampus griseus, is a deep-sea cetacean with a predominantly teuthophagous diet. Its distribution in the northwest Mediterranean is generally in deeper waters, but there is little information on diet or feeding areas. To extend knowledge of the diet of G. griseus, the stomach contents of six stranded Risso's dolphins in the Mediterranean Sea were analyzed. A total of 578 cephalopod beaks (166 uppers and 392 lowers) were found, identified as 386 individuals from 19 different species of Coleoidea cephalopods, one Sepiolida, eight Octopoda, and ten species belonging to the Order Oegopsida. This adds six species of cephalopods to those previously recorded in the Mediterranean Sea: Rondeletiola minor, Eledone moschata, Scaeurgus unicirrhus, Bathypolypus sponsalis, Pteroctopus tetracirrhus and Taonius pavo. In this study the most abundant prey family was Histioteuthidae. In addition, based on the available literature, the diet of 39 Risso's dolphins was reviewed in Mediterranean waters. The abundance of cephalopod species in the diet of these specimens was compared according to genus, geographical area, season, and age. The habitat of the prey of G. griseus was reviewed, suggesting a teuthophagous diet in this area. This study helps to identify both the prey species and the areas where prey are available in the northwest Mediterranean, which are key factors in establishing the limits and regulations of the “Northwest Mediterranean Sea, Slope and Canyon IMMA System” (Important Areas for Marine Mammals) proposed by the Working Group on Marine Mammal Protected Areas (MMPATF - IUCN)Funding for open access charge: Universidade de Vigo/CISUGWith the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)Peer reviewe

Bottlenose dolphin abundance in the NW Mediterranean: addressing heterogeneity in distribution

Line-transect estimators were developed to assess abundance of coastal dolphins Tursiops truncatus and Stenella coeruleoalba encountered in low densities during aerial sighting surveys. The analysis improved on conventional approaches by objectively combining data from different species, survey areas and other covariates affecting dolphin delectability. Model selection and multimodel inference allowed robust estimates of precision in accounting for covariate selection uncertainty. These methods were used to estimate bottlenose dolphin abundance in NE Mediterranean waters that included a putative subpopulation in the Balearic Islands. Total abundance was estimated as 7654 (coefficient of variation, CV = 0.47; 95% CI = 1608 to 15 766) and the abundance in inshore waters of the Balearic Islands varied from 727 (CV = 0.47; 95% Cl = 149 to 148 1) dolphins in spring 2002 to 1333 (CV = 0.44; 95% CI = 419 to 2617) dolphins in autumn 2002, with an average estimate of 1030 (CV = 0.35; 95% Cl = 415 to 1849). The results do not support an exclusively coastal Balearic Island subpopulation, but they strongly indicate that the islands contain critical habitats required for the conservation of the species. Given the observed decline of the species during the last few decades, conservation-oriented management should focus on reducing or eliminating adverse fishing interactions while key areas are protected from encroachment produced by human development