Application of multistate modeling to estimate salmonid survival and movement in relation to spatial and temporal variation in metal exposure in a large mining-impacted river

Canadian Journal of Fisheries and Aquatic Sciences
By: , and 

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Abstract

We used telemetry and multistate modeling to estimate survival and movement of brown trout Salmo trutta and westslope cutthroat trout Oncorhynchus clarkii lewisi in relation to dissolved copper concentrations in 189 km of the upper Clark Fork River, Montana, a mining-impacted river in western Montana. Annual survival estimates for both brown trout (range, 0.27-0.53) and westslope cutthroat trout (range, 0.001-0.34) over the three-year study were low and variable within the study area, with survival negatively related to level of copper exposure. Survival probability for brown trout and westslope cutthroat trout in the uppermost river segment, where dissolved copper concentrations frequently exceeded acute criteria for aquatic life (range, 31-60 d >13.4 µg·L-1), was 2.1 times and 122 times lower, respectively, compared to survival rates in the lowermost segment that had relatively low dissolved copper (0 d exceedance of acute concentration). Seasonal differences in survival also appeared to be related to copper exposure level. Lowest survival for both species occurred in the spring-summer period when dissolved copper concentrations were elevated coincident with higher discharge. Movement among study segments was generally low, and cutthroat trout in particular showed low movement into the uppermost river segment with the most elevated copper levels. Both species showed high rates of movement into tributaries, which coincided with their respective spawning migrations rather than as an apparent avoidance of elevated copper levels. Our research design provided an uncommon opportunity to directly relate the degree of contaminant exposure to estimates of fish survival and movement at a population-level over a large spatial scale. This linkage between survival rate and level of copper exposure for both brown trout and cutthroat trout in the upper Clark Fork River suggests that additional removal of tailings deposits could improve survival rates.

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Publication type Article
Publication Subtype Journal Article
Title Application of multistate modeling to estimate salmonid survival and movement in relation to spatial and temporal variation in metal exposure in a large mining-impacted river
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/cjfas-2018-0280
Volume 76
Issue 11
Year Published 2019
Language English
Publisher Canadian Science Publishing
Contributing office(s) Northern Rocky Mountain Science Center
Description 12 p.
First page 2057
Last page 2068
Country United States
State Montana
Other Geospatial Clark Fork River
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