High Genetic Heterogeneity in Chum Salmon in Western Alaska, the Contact Zone between Northern and Southern Lineages

Abstract

Genetic relationships among 64 spawning populations of chum salmon Oncorhynchus keta in western Alaska were studied using allele frequency data from 40 protein-encoding loci.

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.…”

“…Glacial recession followed by isostatic rebound could have resulted in stream captures in both areas (e.g., a branch of the Chandalar River by the Koyukuk River and a branch of the Tanana River by the Kuskokwim River). Vicariance induced by glacial recession has been used to explain similar results for salmon elsewhere in Alaska (e.g., Gharrett et al 1987;Seeb and Crane 1999). Alternatively, the three barriers (and other barriers between the coastal and inland groups) may reflect post-glacial secondary contact.…”

Genetic analysis of Dolly Varden (Salvelinus malma) across its North American range: evidence for a contact zone in southcentral Alaska

“…For instance, Seeb and Crane (1999) studied allozyme variation in chum salmon (Oncorhynchus keta) and reported a contact zone between Beringian and Cascadian lineages across a 150 km wide stretch of the northwestern portion of the Alaska Peninsula. Chignik Lake falls within this zone on the southern portion of the Alaska Peninsula.…”

“…Chignik Lake falls within this zone on the southern portion of the Alaska Peninsula. Seeb and Crane (1999) also noted that this general area is thought to be a contact zone between two human aboriginal language groups: Aleut and Yu'pik (Muller-Beck 1967). O' Corry-Crowe et al (1997) and Westlake and O'Corry-Crowe (2002) used mtDNA to resolve major distinctions between populations within both beluga whales (Delphinapterus leucas) and harbor seals (Phoca vitulina) sampled north and south of the Alaska Peninsula and suggested that the peninsula may represent a major biogeographical boundary.…”

“…The vast majority of studies of population structure of North American Dolly Varden have occurred in Alaska, and there is virtually nothing known of the population structure of Dolly Varden south of the Alaska Panhandle despite the widespread occurrence of the species throughout coastal British Columbia and portions of western Washington State. In addition, areas from the Bering Sea south to the Alexander Archipelago in southeastern Alaska have been associated with contact zones in a variety of aquatic and terrestrial taxa (e.g., Seeb and Crane 1999;Cook et al 2001;Hoffman et al 2006). Given the evidence for two groups of Dolly Varden and the proposal that the Alaska Peninsula is a point of separation between the forms, more intensive sampling of Dolly Varden across its North American range may resolve a zone of contact between northern and southern Dolly Varden.…”