Dworshak Dam Impact (Impacts) Assessment and Fishery Investigation.
Kokanee abundance, estimated from July trawl data, was 1.2 million fish in 1988, including 553,000 fry, 501,000 yearlings and 156,000 subadults. Spawning trend data indicated escapement was up threefold compared to 1987, despite a sport harvest of 207,000 kokanee averaging 258 mm caught at a rate of 1.5 fish per hour. An estimated 40,000 kokanee were counted during the September peak of spawning in five tributaries of the reservoir. Size of adult fish was below average at 293 mm. Zooplankton densities averaged 10.3 organisms/L in 1988 and ranged from 0.3 organisms/L during April at the Little North Fork station to 26.2 organisms/L in November at the Elk Creek station. Densities were similar to values obtained prior to the development of the primary kokanee fishery; however, cladocerans made up only 34.9% of the zooplankton sampled. Daphnia and Cyclops were the most important food items; Daphnia became the prime food organism as its seasonal abundance increased. Concentrations of ortho-phosphate and nitrate, lower than in the 1970s, indicated Dworshak may have become more oligotrophic. 13 refs., 24 figs., 4 tabs.
- Research Organization:
- Idaho Dept. of Fish and Game, Boise, ID (USA). Fisheries Research Section
- Sponsoring Organization:
- United States. Bonneville Power Administration.
- DOE Contract Number:
- AI79-87BP35167
- OSTI ID:
- 5206908
- Report Number(s):
- DOE/BP-35167-2; ON: DE90004331
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of the Operation of Kerr and Hungry Horse Dams on the Reproductive Success of Kokanee in the Flathead System, 1987 Final Report.
Dworshak Dam Impacts Assessment and Fisheries Investigation Project: Kokanee Entrainment Losses at Dworshak Reservoir, 1996 Annual Progress Report.
Related Subjects
54 ENVIRONMENTAL SCIENCES
DAMS
ENVIRONMENTAL IMPACTS
HYDROELECTRIC POWER
POWER GENERATION
SALMON
POPULATION DYNAMICS
BONNEVILLE POWER ADMINISTRATION
FEEDING
MIGRATION
MITIGATION
PROGRESS REPORT
REMEDIAL ACTION
VARIATIONS
ANADROMOUS FISHES
ANIMALS
AQUATIC ORGANISMS
DOCUMENT TYPES
ELECTRIC POWER
ENERGY SOURCES
FISHES
NATIONAL ORGANIZATIONS
POWER
RENEWABLE ENERGY SOURCES
US DOE
US ORGANIZATIONS
VERTEBRATES
Kodanee salmon - Effect of dams on - Idaho - Dworshak Reservior
130600* - Hydro Energy- Environmental Aspects
540350 - Environment
Aquatic- Site Resource & Use Studies- (1990-)