Evaluating streamflow and temperature effects on Bull Trout migration and survival with linear spatial capture–recapture models.

This article focuses on the migration and survival of fluvial Bull Trout (Salvelinus confluentus) in the Salmon River basin, Idaho, under contrasting streamflow and water temperature conditions from 1992 to 1994, providing insights relevant to climate change impacts. Using radio telemetry and a Bayesian linear spatial capture–recapture model, the study found that prespawning Bull Trout migration distances increased with higher streamflow and water temperature, with survival higher during the low-flow, warmer 1992 season compared to the high and variable flow 1993 season. Postspawning fish exhibited diverse migration and overwintering strategies, with survival remaining relatively constant over a longer period. Habitat complexity influenced detection rates, and the findings suggest that increased streamflow variability and warming associated with future climate change may adversely affect Bull Trout survival and migration patterns, emphasizing the importance of conserving diverse habitats and life history strategies for species persistence.