Genetic Stock Structure of Western Alaska Chum Salmon and a Comparison with Russian Far East Stocks

Abstract

Substantial genetic divergence was found among chum salmon (Oncorhynchus keta) populations collected from North America and Russia. Five major groups of populations can be identified by geographic region: (1) lower Yukon River summer run; (2) upper Yukon River fall run; (3) Bristol Bay area; (4) Alaska Peninsula; and (5) Russia. Mean heterozygosities were 0.064, 0.062, 0.065, 0.064, and 0.063, respectively; and the percent polymorphic loci values at the 0.99 level were 33.7, 31.3, 32.6, 30.6, and 30.9%, respectively. The hierarchical gene diversity analysis showed that 95.42% of the diversity can be explained by heterogeneity within sites, 1.36% among sites, 0.49% between Yukon River run timing, 1.69% among areas, and 1.04% among countries. The Alaska Peninsula populations are genetically more similar to populations from Russia than to those from western Alaska, and two populations from the upper Yukon River are distinct from other nearby populations. Possible reasons for these findings concern the complex glacial histories of the watersheds.

Comparative landscape genetic analysis of three Pacific salmon species from subarctic North America

“…In fact, the SAMOVA results reveal a single collection group for each species that consisted of all or most of the Norton Sound and Kuskowkim River watersheds and the lower Yukon River. Other studies have described low heterogeneity among western Alaska salmon populations (e.g., Gharrett et al 1987;Wilmot et al 1994;Seeb and Crane 1999;Utter et al 2009). The locations of boundaries separating the coastal and inland collections are similar for each species and are identified as partial gene flow barriers.…”

Analysis of F ST outliers at allozyme loci in Pacific salmon: implications for natural selection

“…One exception to this for Pacific salmon examined here are isoforms of the phosphoglucomutase (PGM) enzyme, as PGM loci were F ST outliers in Chinook and sockeye salmon. The allozyme locus mIDHP was found to be a high F ST outlier in both the Phelps et al (1994) and Wilmot et al (1994) analyses on chum salmon. Likewise PGM-1 was a high F ST outlier in both sockeye salmon datasets.…”

“…Studies that used numerous allozyme loci as well as those that included samples from a wide geographic area were chosen. The data sets included two studies on Chinook salmon (O. tshawytshca Walbaum- Bartley et al 1992;Waples et al 2004), two on chum salmon (O. keta Walbaum- Phelps et al 1994;Wilmot et al 1994) and two on sockeye salmon (O. nerka Walbaum- Varnavskaya et al 1994;Wood et al 1994) (Table 1). Allozyme alleles frequencies were taken directly from the publications.…”

“…In some instances complete datasets were not analyzed for F ST outliers, as doing so would combine highly divergent genetic groups and potentially violate assumptions of the simulation model (see below). Examples of this include separate analysis of coastal, Canada, and interior Columbia River (spring-run) Chinook (Waples et al 2004) and separate analysis of chum salmon from Eastern Russia and Western North America (Wilmot et al 1994). The coastal group 1 from Waples et al (2004) includes populations from California, Oregon, coastal Washington, and the lower Columbia River.…”

“…3A). Chum salmon populations from the Yukon River and Bristol Bay area (Wilmot et al 1994) each had one locus with elevated F ST values (sIDHP-2 and LDH-C, respectively: Fig. 4A, B), though these were not statistically significant after Bonferroni corrections.…”