Kokanee Stock Status and Contribution of Cabinet Gorge Hatchery, Lake Pend Oreille, Idaho, 1987 Annual Progress Report.

Technical Report · Sun May 01 00:00:00 EDT 1988

DOI:https://doi.org/10.2172/6199993· OSTI ID:6199993

Bowles, Edward C

Estimated kokanee Oncorhynchus nerka abundance in Lake Pend Oreille was 6.01 million during late summer 1987. This estimate is 40% higher than the 1986 estimate and is the second largest population estimate since 1977. Higher abundance is predominantly a result of enhanced fry survival and recruitment. Hatchery-reared fry contribution was 22% of total fry recruitment in 1987, compared to 8% in 1986, and resulted from a fivefold increase in survival. Much of this improvement can be attributed to the large (52 mm) fry produced at Cabinet Gorge Hatchery in 1987 and represents the first measurable contribution of the new hatchery to the kokanee rehabilitation program. Survival of hatchery-reared fry released into Clark Fork River was nearly one-half that of fry released into Sullivan Springs due to poor flow conditions and potentially high predation during migration from Cabinet Gorge Hatchery to Lake Pend Oreille. Wild fry survival was enhanced by early availability of forage (cladocern zooplankton) during fry emergence in late spring. Cladoceran production began three weeks earlier in 1987 than 1986, which resulted from reduced Mysis abundance and earlier thermal stratification of Lake Pend Oreille, which helped segregate cladocerans from mysid predation. Kokanee dry otolith coding was evaluated to provide a reliable long-term mark. Analysis of daily growth increments on otoliths was used successfully in 1987 to differentiate fry from various release sites. The technique will be refined during 1988 to include coding fry otoliths with water temperature fluctuations during hatchery residence. 23 refs., 20 figs., 2 tabs.

• Research Organization: Idaho Dept. of Fish and Game (IDFG)
• Sponsoring Organization: United States. Bonneville Power Administration.
• DOE Contract Number: 1985BP22493
• OSTI ID: 6199993
• Report Number(s): DOE/BP-22493-3; R&D Project: 1985-339-00; ON: DE89011520
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products; Related Information: May 1987 from cover page.
• Country of Publication: United States
• Language: English

Related Subjects

13 HYDRO ENERGY
54 ENVIRONMENTAL SCIENCES
POWER GENERATION
ENVIRONMENTAL IMPACTS
SALMON
MIGRATION
BONNEVILLE POWER ADMINISTRATION
IDAHO
POPULATION DYNAMICS
PROGRESS REPORT
REPRODUCTION
ANADROMOUS FISHES
ANIMALS
AQUATIC ORGANISMS
DOCUMENT TYPES
FEDERAL REGION X
FISHES
NATIONAL ORGANIZATIONS
NORTH AMERICA
US DOE
US ORGANIZATIONS
USA
VERTEBRATES
Kokanee salmon - Geographical distribution
130600* - Hydro Energy- Environmental Aspects
520500 - Environment
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