| Summary: | Poster.-- 35th Annual European Cetacean Society Conference, Catania (Italy), April 10-12 2024 Galicia stranding network (CEMMA) registered a mean of 227 strandings of cetaceans yearly since 2000. In decreasing order, the most frequently stranded species were common dolphins (Delphinus delphis), bottlenose dolphins (Tursiops truncatus), striped dolphin (Stenella coeruleoalba), and harbour porpoises (Phocoena phocoena). In a previous retrospective study (1990-2022), we found that, of the stranded cetaceans examined, 41.4% presented evidence of fishery interactions (e.g., stranded with remains of nets, skin cuts, net impressions, perforations, fractures, amputations of the dorsal fin, caudal flukes or peduncle). During 2023, a total of 618 cetaceans stranded in Galicia. The number of stranded common dolphins was 3.5 times the average from historical data (459/132). In addition, a much high proportion of strandings occurred in the second half of the year. This trend of increased strandings apparently continues in 2024, with more than 50 cetaceans stranded in the first week of January. External examinations carried out on 226 relatively fresh stranded cetaceans (decomposition code 2-3) revealed that (at least) 49.5% of the common dolphins examined presented external lesions compatible with bycatch (91/184), also 9.1% of bottlenose dolphins (1/11), and 50% of harbour porpoises (3/6). Statistical analysis revealed significant increases in common dolphin (p=0.00) and bottlenose dolphin (p=0.039) bycatch mortality over time but no significant change in porpoise bycatch mortality (p=0.188), although it has been increasing since 2010. In addition, two individuals died due to other anthropogenic threats: an adult Cuvier’s beaked whale (Ziphius cavirostris) due to massive plastic ingestion and a fin whale calf (Balaenoptera physalus) killed by ship strike. No external evidence of infectious epidemic disease was detected. Ongoing histopathological and molecular results determine if there is any change in the health status ...
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