Grey seals (Halichoerus grypus) of the North-east Atlantic are protected at designated European Marine Sites (Special Areas of Conservation, SACs) typically during their reproductive periods and in the UK at Sites of Special Scientific Interest (SSSI). As a mobile marine species, grey seals spend other parts of their annual life cycle in non-designated habitat. There is limited information on individual grey seal movements in south-west England. Citizen science photo identification (PID) revealed the movements of 477 grey seals at a regional scale (54 haul-outs up to 230 km apart) for over a decade. Reconstructed movements showed considerable individual variability. Four SACs were linked to up to 18 non-designated sites and two SSSIs in Cornwall were linked to a maximum of 41 non-designated sites. Observations support the value of existing SSSIs at both the well-connected West and North Cornwall sites. Thirteen Marine Protected Areas (MPAs) were visited by grey seals from four SACs and two SSSIs in Cornwall. As a mobile species, grey seals could be included in English MPA management plans. The application of functional linkage from SACs and SSSIs, informed by the movements evidenced in this research, could aid management efforts. This analysis reveals grey seal movements occur across a complex network of interconnected designated and non-designated sites that need to be managed holistically for this species for which the UK has a special responsibility.
Few investigations have examined the pathology of grey seals Halichoerus grypus in southwest England, where it is the most abundant marine mammal. Here, primary pathological findings are presented from 107 post-mortem examinations of grey seals in southwest England between 2013 and 2020. Over three-quarters were pups in their first year of life; the origins of the carcasses reflected the known breeding season and breeding sites of grey seals in the region. Trauma was the most common primary pathological finding (n = 49), followed by infectious disease (n = 36). Traumatic findings included fisheries-related trauma (n = 15), other acute physical traumas (n = 15) and other chronic traumas (n = 19). Infectious disease findings included respiratory infections (n = 21) and gastrointestinal infections (n = 9). There was no difference in the primary pathological findings for seals found dead or that died or were euthanased on the day they were found compared to those dying in early rehabilitation, suggesting that it is appropriate to include findings from seals in early rehabilitation in studies of wild grey seal pathology. Seals that had not been frozen before post-mortem examination were nearly twice as likely to have a primary pathological finding of infectious disease or trauma than those that had been frozen, highlighting the need, wherever possible, to avoid freezing seals prior to post-mortem examination.
Wildlife rescue and rehabilitation is used globally to aid the conservation and welfare of marine species, however, postrelease monitoring is challenging. Here, long‐term, regional postrelease monitoring provides feedback for rehabilitation centers for gray seals (Halichoerus grypus). Data from 1,094 rehabilitated gray seals over 19 years across the southwest UK were examined to assess postrelease survivorship and the impact of release site on movements and range. Using flipper tags combined with photo identification, 391 rehabilitated seals (35.7%) were resighted, including 188 seals (17.2%) that were traced back to a specific rehabilitated individual with release data. The maximum monitoring duration for a single rehabilitated seal was 17 years, although the majority (151/188; 80%) were sighted for less than 5 years and 80/188 (43%) were resighted for less than a year. Almost all 188 traced rehabilitated seals (n = 176, 93.6%) visited the St Ives Bay Wild Site, yet only half had been released at the adjacent St Ives Bay Release Site. Rehabilitated seals had similar dispersal patterns to their wild conspecifics but over a smaller area. Once released, rehabilitated animals face the same threats as their wild counterparts.
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