Mitochondrial DNA variation and genetic population structure of chum salmon Oncorhynchus keta around the Pacific Rim

Abstract

A survey of mtDNA variation among populations of chum salmon Oncorhynchus keta around the Pacific Rim revealed four large population groups: Rim of the Sea of Japan, the Rim of the Okhotsk Sea and West Bering Sea, North‐west Alaska and Gulf of Alaska. The observed population structure appears to reflect isolation by distance with limited gene flow between regions and larger amounts of gene flow between populations within these four regions.

Population Genetic Structure and Phylogeography of Masu Salmon (Oncorhynchus Masou Masou) Inferred from Mitochondrial and Microsatellite DNA Analyses

“…A low influence of isolation by distance may be related to the high homing ability of masu salmon (Okazaki 1986), which may lead to distance-independent genetic differentiation among populations by region. In fact, another Pacific salmon, chum salmon, with less accurate homing ability than masu salmon (Salo, 1991), shows clear population differentiation with isolation by distance around the Pacific Rim (Yoon et al, 2008). Besides the biological consequence, the inference from NCPA may indicate that the historical demography of masu salmon was driven by cycles of glaciation and associated sea level changes (Nürnberg and Tiedemann, 2004).…”

Nonrandom distribution of chum salmon stocks in the Bering Sea and the North Pacific Ocean estimated using mitochondrial DNA microarray

“…Of 32 haplotypes reported [7], three major haplotypes (A1, B3, and C1) were frequently detected in the ocean samples as in the previous report [13], although 17 haplotypes, including 3 (A4, A5, and A7) from clade A, 12 (B2, B5, B6, B7, B11, B12, B13, B15, B16, B17, B18, and B19) from clade B, and 2 from clade C (C3 and C4), mostly infrequent in the baseline [7], were not detected in the present summer collections. It is conceivable that rare haplotypes in the baseline were hardly detected in the ocean as in the previous report [13].…”

“…In the present study, the mtDNA data sets of 96 combined chum salmon population samples in the Pacific Rim [7] (supplementary tables available at http://www.marinenuri. or.kr/website.pdf.…”

“…Recruitment of additional 48 populations provided two novel haplotypes of B-11 and B-16, thereby giving a total of 32 haplotypes in 4,245 fish from the combined 96 populations [7] (data available at http://www.marinenuri. or.kr/website.pdf), although the two novel haplotypes were not included in the DNA microarray employed herein.…”

“…Molecular markers such as nuclear and mitochondrial (mt)DNA markers are expected to become a powerful means with increased accuracy and resolution for genetic stock identification (GSI) of ocean chum salmon [2], as compared with GSI using allozyme variation [1,3,4]. Analyses of nucleotide sequence detected a greater variation in the chum mtDNA control region than the variation observed by the analyses of restriction fragment length polymorphisms (RFLPs), in terms of the increased number of variable nucleotide sites and haplotypes in fish from nearly 100 Pacific Rim spawning populations [5][6][7]. Their mtDNA data suggested substantial genetic differentiation among and within regional groups of chum populations in the Pacific Rim [6,7], suggesting increased potential of mtDNA sequence analyses with better estimation of stock composition in mixed ocean aggregates of chum salmon [6].…”