Abstract
Noxon Rapids and Cabinet Gorge Reservoirs are run-of-the-river hydroelectric impoundments on the Clark Fork River in western Montana. Operations at Noxon Rapids Reservoir changed in 1961 and 1978. The first change in operations increased average annual spring drawdown from less than 10 to more than 30 feet. The second eliminated drawdowns of more than 6 feet, except for unusual power demands. Establishment and maintenance of a satisfactory sport fishery has been largely unsuccessful in both reservoirs since the 1950's. Rainbow trout (Salmo gairdneri) exhibited potential from 1958 through 1960 when they produced an excellent fishery, followed by a dramatic decline in 1961. Continued planting of rainbow trout never reestablished a substantial fishery. Other fish species planted produced similar results with the exception of brown trout (Salmo trutta) and small mouth bass (Micropterus dolomieui), which presently provide a modest fishery. Largemouth bass (Micropterus salmoides) were present prior to impoundment and appear to be increasing. Operation changes, combined with the brief retention times, have encouraged the downstream movement of most introduced salmonids in Noxon Rapids and Cabinet Gorge Reservoirs.
Start Date
19-4-1985 12:00 AM
End Date
19-4-1985 12:00 AM
Document Type
Presentation
Past, Present, and Future Fishery Management in Cabinet Gorge and Noxon Rapids Reservoirs
Noxon Rapids and Cabinet Gorge Reservoirs are run-of-the-river hydroelectric impoundments on the Clark Fork River in western Montana. Operations at Noxon Rapids Reservoir changed in 1961 and 1978. The first change in operations increased average annual spring drawdown from less than 10 to more than 30 feet. The second eliminated drawdowns of more than 6 feet, except for unusual power demands. Establishment and maintenance of a satisfactory sport fishery has been largely unsuccessful in both reservoirs since the 1950's. Rainbow trout (Salmo gairdneri) exhibited potential from 1958 through 1960 when they produced an excellent fishery, followed by a dramatic decline in 1961. Continued planting of rainbow trout never reestablished a substantial fishery. Other fish species planted produced similar results with the exception of brown trout (Salmo trutta) and small mouth bass (Micropterus dolomieui), which presently provide a modest fishery. Largemouth bass (Micropterus salmoides) were present prior to impoundment and appear to be increasing. Operation changes, combined with the brief retention times, have encouraged the downstream movement of most introduced salmonids in Noxon Rapids and Cabinet Gorge Reservoirs.