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Long-term population dynamics and conservation risk of migratory bull trout in the upper Columbia River basin

March 24, 2018

We used redd count data from 88 bull trout (Salvelinus confluentus) populations in the upper Columbia River basin to quantify local and regional patterns in population dynamics, including adult abundance, long-term trend, and population synchrony. We further used this information to assess conservation risk of metapopulations using eight population dynamic metrics associated with persistence. Local population abundances were generally low (<20 redds annually) and the majority of trends were either stable (85%) or declining (13%). Evidence of synchrony among populations was apparent but not related to fluvial distance between streams. Variability in annual abundances was 1.4–2.5 times lower in metapopulations than local populations, indicating moderate portfolio effects across the regional stock complex. Importantly, most metrics of conservation risk were uncorrelated with one another, emphasizing that multiple statistics describing population dynamics at various scales are needed for monitoring and assessing recovery. We provide a composite description of conservation risk based on local and regional population dynamics that can help inform conservation management decisions for bull trout and other freshwater fishes.

Citation Information

Publication Year 2018
Title Long-term population dynamics and conservation risk of migratory bull trout in the upper Columbia River basin
DOI 10.1139/cjfas-2017-0466
Authors Ryan Kovach, Jonathan Armstrong, David Schmetterling, Robert Al-Chokhachy, Clint C. Muhlfeld
Publication Type Article
Publication Subtype Journal Article
Series Title Canadian Journal of Fisheries and Aquatic Sciences
Series Number
Index ID 70210225
Record Source USGS Publications Warehouse
USGS Organization Northern Rocky Mountain Science Center