Date of Award:
5-2002
Document Type:
Thesis
Degree Name:
Master of Science (MS)
Department:
Wildland Resources
Department name when degree awarded
Fisheries and Wildlife
Committee Chair(s)
Jeffrey L. Kershner
Committee
Jeffrey L. Kershner
Committee
Todd Crowl
Committee
Jim Dobrowolski
Abstract
The majority of interior cutthroat trout (Oncorhynchus clarki) subspecies have been extirpated from large rivers by anthropogenic activities that have fragmented habitats and introduced non-native competitors. Selective pressures against migratory behaviors and mainstream river occupation and conservation schemes that isolate genetically pure populations above barriers have restricted gene flow and prevented the expression of fluvial life history traits in many populations. Existing knowledge about the movements and home range requirements of fluvial cutthroat trout is therefore limited. We implanted a total of 55 Bonneville cutthroat trout (BCT) in the Thomas Fork River, Idaho, with radio transmitters and located them weekly or bimonthly from October to April of both 1999/2000 and 2000/2001. Half of these fish were located above a seasonal diversion barrier and half were located below. We found fish to be more mobile than previously reported. Individuals located above the diversion barrier in 2000/2001 occupied significantly larger home ranges (median 3,675 m, range 2,500-8,900 m) and moved more frequently (mean 0.89 movements/contact, range 0.57-1.0) than other fish. Fish occupied habitats in the lower Thomas Fork and Bear River during the winter that were marginal or uninhabitable during other seasons. During the spring of both years we located fish in both upstream and neighboring 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 and its tributaries and suggest that successful efforts at conservation of these fish will focus on mainstream habitats and the maintenance of seasonal migration corridors.
Checksum
9a02ce89dc3e816f306e1b2b7d8d8059
Recommended Citation
Colyer, Warren, "Seasonal Movements of Fluvial Bonneville Cutthroat Trout in the Thomas Fork of the Bear River, Idaho-Wyoming" (2002). All Graduate Theses and Dissertations, Spring 1920 to Summer 2023. 4435.
https://digitalcommons.usu.edu/etd/4435
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