title: Genetic analysis of sympatric migratory ecotypes of Arctic charr Salvelinus alpinus: alternative mating tactics or reproductively isolated strategies?
abstract: Three populations of Arctic charr Salvelinus alpinus from southern Baffin Island were previously identified to display variable migratory phenotypes, with an anadromous component of the population and another remaining resident in fresh water. In this study, 14 microsatellite markers were used to help distinguish between two alternative hypotheses to explain the co-existence of the two ecotypes: that the two ecotypes originate from a single population and are the result of a conditional mating tactic or that the migratory ecotypes are reproductively isolated populations utilizing alternative migratory strategies. In two of the three replicate systems, F(ST) values between the resident and anadromous individuals were non-significant, while they were significant in a third sampling location. Bayesian clustering analysis implemented in structure, however, failed to identify any within-location clustering in all three sampling locations. It is concluded from these analyses that the life-history ecotypes are most likely conditional mating tactics, rather than reproductively isolated populations. Other evidence in favour of the alternative mating tactic hypothesis is briefly reviewed, and implications for management of those populations are discussed.
authors.affiliation: Department of Zoology and Beaty Biodiversity Research Centre and Museum, University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4 Canada.
authors.forename: J-S
authors.initials: JS
authors.lastname: Moore
authors.forename: T N
authors.initials: TN
authors.lastname: Loewen
authors.forename: L N
authors.initials: LN
authors.lastname: Harris
authors.forename: R F
authors.initials: RF
authors.lastname: Tallman
mesh_terms: D025041:Animal Migration; D000818:Animals; D001499:Bayes Theorem; D016000:Cluster Analysis; D060146:Ecotype; D005828:Genetics, Population; D018895:Microsatellite Repeats; D020957:Nunavut; D060047:Reproductive Isolation; D017422:Sequence Analysis, DNA; D012726:Sexual Behavior, Animal; D014337:Trout / Q000235:genetics*
keywords: Baffin Island; anadromy; life history; microsatellites; reproductive isolation; salmonids