Stock identification studies of high seas salmon in Japan: a review and future
manage salmon internationally, stock identification is indispensable to determine ocean distributions and abundance. In Japan, tag release, scale pattern, parasites, genetic variation, and otolith mark are mainly used to estimate the geographical origin of salmon in the ocean. In collaboration with...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.613.2320 http://www.npafc.org/new/publications/Technical Report/TR5/page 9-10(Urawa).pdf |
| Summary: | manage salmon internationally, stock identification is indispensable to determine ocean distributions and abundance. In Japan, tag release, scale pattern, parasites, genetic variation, and otolith mark are mainly used to estimate the geographical origin of salmon in the ocean. In collaboration with the North Pacific Rim countries, intensive salmon tagging experiments have been conducted on the high seas since 1956. Recovery information indicated ocean migration routes of major stocks of maturing sockeye, chum, pink, and coho salmon (Ogura 1994). However, the tagging information was insufficient to clarify the distribution and abundance of major salmon stocks throughout the entire ocean life including juvenile and overwintering periods. The migration route of Japanese chum salmon was estimated using recent information on fish abundance and genetic stock identification (GSI) of mixtures (n = 6,400) sampled on the high seas in 1993–99 (Urawa 2000). A genetic baseline of 20 allozyme loci from major stocks throughout the North Pacific Rim was employed. The GSI results showed that Japanese chum salmon globally shift their marine distribution depending on the life stage and season (Fig. 1). Juveniles are distributed in the Okhotsk Sea during summer and fall, but are confined to a narrow band (SST 4–6ºC) of the western North Pacific during the first winter. Young salmon enter the Bering Sea by the next summer. In the late fall, immature chum salmon move southeast to the Gulf of Alaska for the second wintering. They migrate between summer feeding grounds in the Bering Sea and winter habitat in the Gulf of |
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