Movement patterns, habitat use, and survival of Lahontan cutthroat trout in the Truckee River

Habitat fragmentation, hybridization, and competition with nonnative salmonids are viewed as major threats to Lahontan cutthroat trout Oncorhynchus clarkii henshawi. Understanding Lahontan cutthroat trout behavior and survival is a necessary step in the reintroduction and establishment of naturally reproducing populations of Lahontan cutthroat trout. We used weekly radiotelemetry monitoring to examine movement patterns, habitat use, and apparent survival of 42 hatchery-reared Lahontan cutthroat trout in a 16.5-km stretch of the Truckee River, Nevada, across three reaches separated by barriers to upstream movement. We found differences in total movement distances and home range sizes of fish in different reaches within our study area. Fish used pool habitats more than fast water habitats in all reaches. Time of year, stream temperature, and fish standard length covariates had the strongest relationship with apparent survival. Monthly apparent survival was lowest in January, which coincided with the lowest flows and temperatures during the study period. Our results verify the mobility of Lahontan cutthroat trout and indicate that conditions during winter may limit the survival and reintroduction success in the portions of the Truckee River evaluated in this study.