title: Low levels of hybridization between sympatric Arctic char (Salvelinus alpinus) and Dolly Varden char (Salvelinus malma) highlights their genetic distinctiveness and ecological segregation.
abstract: Understanding the extent of interspecific hybridization and how ecological segregation may influence hybridization requires comprehensively sampling different habitats over a range of life history stages. Arctic char (Salvelinus alpinus) and Dolly Varden (S. malma) are recently diverged salmonid fishes that come into contact in several areas of the North Pacific where they occasionally hybridize. To better quantify the degree of hybridization and ecological segregation between these taxa, we sampled over 700 fish from multiple lake (littoral and profundal) and stream sites in two large, interconnected southwestern Alaskan lakes. Individuals were genotyped at 12 microsatellite markers, and genetic admixture (Q) values generated through Bayesian-based clustering revealed hybridization levels generally lower than reported in a previous study (<0.6% to 5% of samples classified as late-generation hybrids). Dolly Varden and Arctic char tended to make different use of stream habitats with the latter apparently abandoning streams for lake habitats after 2-3 years of age. Our results support the distinct biological species status of Dolly Varden and Arctic char and suggest that ecological segregation may be an important factor limiting opportunities for hybridization and/or the ecological performance of hybrid char.
authors.affiliation: Department of Zoology, Biodiversity Research Centre and Beaty Biodiversity Museum, University of British Columbia 6270 University Ave., Vancouver, BC, Canada, V6T 1Z4.
authors.forename: Shannan L
authors.initials: SL
authors.lastname: May-McNally
authors.affiliation: School of Aquatic and Fishery Sciences, University of Washington Seattle, Washington, 98195.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Quinn
authors.affiliation: Department of Zoology, Biodiversity Research Centre and Beaty Biodiversity Museum, University of British Columbia 6270 University Ave., Vancouver, BC, Canada, V6T 1Z4.
authors.forename: Eric B
authors.initials: EB
authors.lastname: Taylor
keywords: Ecological segregation; Salvelinus; hybridization; microsatellites; sympatric populations