UBC Theses and Dissertations
Bull trout (Salvelinus confluentus) spawning migrations in the Duncan River : insights from telemetry and DNA O'Brien, David Sean
Radio telemetry and microsatellite DNA analyses were used to describe spawning migrations and the spatial scale of genetic differentiation among populations of bull trout (Salvelinus confluentus) in the Duncan River system, southeastern British Columbia. Over two years, 66 radio-tagged bull trout were tracked to destinations in the upper Duncan River. The distribution of bull trout by destination in the upper Duncan River and migration timing among all destinations did not vary between the two study years. One third o f bull trout tracked for two spawning migrations switched spawning stream from one year to the next. There was also a trend for increasing size of radio-tagged bull trout with spawning stream size. This suggests that bull trout in the upper Duncan River do not have fidelity at the scale of individual spawning stream. Microsatellite DNA analysis of juvenile bull trout from two spawning streams in the upper Duncan River indicate that there is little between stream variation. Exact tests of population differentiation over allele frequencies of six polymorphic microsatellite loci suggest no significant genetic differentiation between the two spawning streams. An analysis of molecular variance (AMOVA) partitioned a small (< 1%) but significant amount of genetic variance to the between spawning stream variance partition. The estimate of between spawning stream FST was 0.01. These estimates of l ow genetic variation between spawning streams, especially when combined with direct evidence from telemetry, suggest that bull trout in the upper Duncan River do not home at the scale of individual spawning streams.
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