Genetic Stock Identification of Chum Salmon in the Bering Sea and North Pacific Ocean Using Mitochondrial DNA Microarray

Abstract

A newly developed DNA microarray was applied to identify mitochondrial (mt) DNA haplotypes of more than 2200 chum salmon in the Bering Sea and North Pacific Ocean in September 2002 and also 2003, when the majority of maturing fish were migrating toward their natal river. The distribution of haplotypes occurring in Asian and North American fish in the surveyed area was similar in the 2 years. A conditional maximum likelihood method for estimation of stock compositions indicated that the Japanese stocks were distributed mainly in the north central Bering Sea, whereas the Russian stocks were mainly in the western Bering Sea. The North American stocks were abundant in the North Pacific Ocean around the Aleutian Islands. These results indicate that the Asian and North American stocks of chum salmon are nonrandomly distributed in the Bering Sea and the North Pacific Ocean, and further the oligonuleotide DNA microarray developed by us has a high potential for identification of stocks among mixed ocean aggregates of high-seas chum salmon.

Activity of the pituitary–gonadal axis is increased prior to the onset of spawning migration of chum salmon

“…Populations of chum salmon in the Bering Sea are composed of many stocks from the rivers in the Pacific Rim. The previous stock identification of individuals from mtDNA haplotypes showed that Japanese chum salmon were the dominant stock distributed in the central Bering Sea in 2002and 2004(Moriya et al, 2007Sato et al, 2007).…”

“…The hypothesis for the route of oceanic migration of chum salmon indicates that winter chum salmon of the Japanese population leave the Gulf of Alaska for the Bering Sea in spring (Urawa, 2000). In summer before the commencement of spawning migration, chum salmon originating in Japan form mixed populations with stocks from other geographical areas of the Pacific Rim in the Bering Sea, although Japanese populations are distributed mainly in the central Bering Sea (Moriya et al, 2007;Sato et al, 2007). Homing adults, which leave the Bering Sea in early summer, require two to three months to reach their natal rivers in Japan (Tanaka et al, 2005).…”

Changes in the plasma levels of insulin-like growth factor-I from the onset of spawning migration through upstream migration in chum salmon

“…Chum salmon in the Bering Sea form mixed populations whose stocks originate in the North Pacific Rim. Analyses of mitochondrial DNA (mtDNA) haplotypes showed that a considerable portion of chum salmon in these areas belongs to Japanese populations (Moriya et al, 2007;Sato et al, 2006;Sato et al, 2007).…”

Preliminary estimation of chum salmon stock composition in the Bering Sea and North Pacific Ocean using polymorphic microsatellite DNA markers

“…Even though DNA markers are expected to compensate deficits of the use of allozyme analysis with increased accuracy and resolution for GSI analysis, only a few published papers have reported the utility of chum salmon mtDNA variation for GSI (Seeb and Crane 1999;Moriya et al 2007). In particular, Moriya et al (2007) applied sequence analysis for mixed-stock analysis to estimate the origin of stocks and their composition in the Bering Sea and North Pacific Ocean, and found non-random distribution of Japanese, Russian, and North American stocks in the surveyed area.…”

“…In particular, Moriya et al (2007) applied sequence analysis for mixed-stock analysis to estimate the origin of stocks and their composition in the Bering Sea and North Pacific Ocean, and found non-random distribution of Japanese, Russian, and North American stocks in the surveyed area.…”