Population genetics of Bull Trout ( Salvelinus confluentus ) in the Upper Athabasca river basin

Abstract

Across its native range, Bull Trout (Salvelinus confluentus) extent and abundance are in decline due to historic overharvest and habitat degradation. Because Bull Trout are dependent on extensively connected, cold, clean headwater habitats, fragmentation from land use changes causes difficulty when determining the true extent and health of their populations, with Bull Trout of Albertas Eastern Slope region being no exception. Across this region, 431 Bull Trout from 20 sites were sampled from the Athabasca and Saskatchewan River basins and compared using 10 microsatellite loci to characterize within- and among-population genetic variation. The Saskatchewan and Athabasca River basins contained similar levels of heterozygosity but were differentiated from one another. Within the Athabasca River basin, five genetically differentiated clusters were found. Additionally, no isolation-by-distance pattern was observed between these sites. These results suggest these populations have ample genetic diversity, but genetic differentiation should be considered when deciding whether and how to alter connectivity between populations.