Distribution and abundance of the largha seal (Phoca largha Pall.) on the coast of Primorye Region (Russia): a literature review and survey report

抄録

Long-term studies (1963-2000) of a local population of the largha seal Phoca largha in the waters of Primorye Region were reviewed. In winter, largha seals were observed mainly in the southern coast of Primorye (the Peter the Great Bay: PGB). In contrast, abundance was low along the eastern coast of Primorye, where waters were mostly open throughout the winter. In summer and fall, numbers decreased in PGB, whereas those along the eastern coast of Primorye increased. This might reflect seal movements between PGB and the eastern coast. The majority of the coastal haul-out sites were confined to the protected zone of the Far Eastern Marine Reserve in PGB, and seals used PGB haul-out sites year round. The results of seal tagging studies on the Rimskii-Korsakov Islands in PGB, suggest that largha seals are able to move far to the north from PGB, reaching the Sea of Okhotsk waters and the Pacific coast of Hokkaido, Japan. Population size was estimated recently to be about one thousand individuals. Further growth of the population may be limited by incidental take by the trap net fishery in PGB waters in winter, which accounts for up to 10% of annual mortality.