Evidence of panmixia between sympatric life history forms of coastal cutthroat trout in two lower Columbia River tributaries

North American Journal of Fisheries Management
By: , and 

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Abstract

Coastal cutthroat trout Oncorhynchus clarkii clarkii exhibit resident and migratory life history strategies that often occur sympatrically, but the relationship between these forms within a population is poorly characterized. Through use of passive integrated transponder technology, migratory and resident coastal cutthroat trout were identified in two lower Columbia River tributaries (Abernathy Creek and the Chinook River) separated by more than 80 km. Genetic data from 17 highly variable microsatellite loci were used to ascertain the genetic population structure of these life history forms within and between streams. No distinct genetic separation was observed between the life history forms within a stream, as assessed by four different statistical approaches: permutation tests based on the genetic differentiation index F ST, principal components analysis of individuals, analysis of molecular variance, and contingency tests of allele frequency heterogeneity. Genetic differences were an order of magnitude higher between stream samples (F ST > 0.03) than between life history forms within a stream (F ST < 0.003). The contingency test detected allele frequency differences between migratory and resident life history forms in Abernathy Creek (P = 0.001), but this result was influenced more by age-class structure than by reproductive isolation between life history forms. Results are consistent with a single, randomly mating population in each stream producing both migratory and resident life history forms. These data suggest that individual life history strategy in coastal cutthroat trout is predominantly determined by phenotypic plasticity rather than genotype.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Evidence of panmixia between sympatric life history forms of coastal cutthroat trout in two lower Columbia River tributaries
Series title North American Journal of Fisheries Management
DOI 10.1577/M09-055.1
Volume 30
Issue 3
Year Published 2010
Language English
Publisher Taylor & Francis
Contributing office(s) Coop Res Unit Leetown
Description 11 p.
First page 691
Last page 701
Country United States
State Washington
Other Geospatial Abernathy Creek, Chinook River, Columbia River