日本におけるスナメリの系群構造-系群と分布に関する3つの話題

摘要

Stock origin of a vacant female finless porpoise found at Shimizu port, Shizuoka, was identified. The port is in outer side of five coastal waters (Sendai Bay-Tokyo Bay, Ise-Mikawa Bays, Inland Sea-Hibiki nada, Omura Bay, and Ariake Sound-Tachibana Bay)，which are main distributional area of Japanese porpoises. From geographic variation revealed in mitochondrial DNA (mtDNA) control region sequences among the waters, porpoises in each of the waters are thought to belong to distinct stock. mtDNA control region sequence obtained from the female obtained at Shimizu was compared with 10 haplotypes that were found in 174 Japanese porpoises and then deposited in GenBank. The female sequence matched a haplotype from animals collected only in Ise-Mikawa Bays, which suggests that the female came from the bays. From stranded-bycaught porpoise datasets, animal occurrence in western part of the Inland Sea - Hibiki Nada stock distributional area (Hibiki Nada and contiguous Genkai Nada) was examined. In the waters, porpoises appear to conduct seasonal migration, i.e., migrate to eastern side in summer and to western side in winter. Karatsu Bay was thought to be the westernmost point of distributional area of the stock.