SPAWNING ECOLOGY OF FINESPOTTED SNAKE RIVER CUTTHROAT TROUT IN SPRING STREAMS OF THE SALT RIVER VALLEY, WYOMING

We studied spawning ecology of cutthroat trout (Oncorhynchus clarki) in streams that originate as springs along the Salt River, a Snake River tributary in western Wyoming. We assessed (1) relative numbers of upstream-migrant and resident adults present during the spawning period in spring streams, (...

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Bibliographic Details
Published in:Western North American naturalist 2004-02, Vol.64 (1), p.78-85
Main Authors: Joyce, Michael P., Hubert, Wayne A.
Format: Article
Language:English
Subjects:
Anadromous fishes
Creeks
Fish weirs
Freshwater
Freshwater fishes
Gravel
Oncorhynchus clarki
Riverine habitats
Stream habitats
Streams
Trout
Wildlife habitats
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Summary:We studied spawning ecology of cutthroat trout (Oncorhynchus clarki) in streams that originate as springs along the Salt River, a Snake River tributary in western Wyoming. We assessed (1) relative numbers of upstream-migrant and resident adults present during the spawning period in spring streams, (2) influence of habitat modification on use of spring streams for spawning, and (3) habitat features used for spawning in spring streams. Four spring streams were studied, 2 with substantial modification to enhance trout habitat and 2 with little or no modification. Modifications consisted primarily of constructing alternating pools and gravel-cobble riffles. Only a small portion of adult fish in spring streams during the spawning period had migrated upstream from the Salt River between March and the middle of June. Larger numbers of adult fish and more redds were observed in the 2 modified streams compared with the 2 streams with little or no modification. Most spawning occurred on constructed riffles with small gravel and over a narrow range of depths and velocities. Cutthroat trout, rainbow trout (Oncorhynchus mykiss), and their hybrids were observed in 1 stream with habitat modifications, indicating that measures to halt invasion by rainbow trout, as well as habitat improvement, are needed to preserve this native trout within the Salt River valley.
ISSN:1527-0904
1944-8341