Seasonal movements of fluvial Bonneville cutthroat trout in the Thomas Fork of the Bear River, Idaho-Wyoming.

摘要

Most interior cutthroat trout subspecies have been extirpated from large rivers by anthropogenic activities that have fragmented habitats and introduced non-native competitors. Selective pressures against migratory behaviors have prevented the expression of fluvial life history traits, and little is therefore known about the spatial requirements of fluvial populations. We used telemetry to track 55 fluvial Bonneville cutthroat trout (BCT) in the Thomas Fork River from October to April of 1999/2000 and 2000/2001. Individuals located above a diversion barrier in 2000/2001 occupied larger home ranges and moved more frequently than others. Fish occupied habitats during the winter that were marginal during other seasons. In spring we tracked fish into tributaries up to 84 km away from our study site. Our results document the existence of a fluvial component of BCT in the Bear River system and suggest that successful efforts at their conservation will require the maintenance of seasonal migration corridors.