Lake Pend Oreille Fishery Recovery Project, 1997-1998 Annual Report.
- Idaho Department of Fish and Game, Boise, ID
The elevation of Lake Pend Oreille was kept 1.2 m higher during the winter of 1997-1998 in an attempt to recover the impacted kokanee fishery. This was the second winter of a scheduled three-year test. Hydroacoustic surveys and trawling were conducted in the fall of 1998 to assess the kokanee population. We estimated the abundance of wild and hatchery fry in the lake at 3.71 million by hydroacoustics. These originated from an estimated 11.2 million eggs spawned during the fall of 1997. The survival from wild spawned eggs to wild fry was 9.7%, which is the highest egg-to-fry survival rate on record. This is the strongest indication to date that higher lake levels were having a direct benefit to the kokanee population. By trawling, we found that total kokanee abundance in the lake dropped to a new record low of 2.8 million fish. The number of adult kokanee in the lake was below average: 100,000 age 4 kokanee (100% mature) and 730,000 age 3 kokanee (29% mature). These fish laid an estimated 52.1 million eggs in 1998. Hatchery personnel collected 9.0 million eggs which were cultured, marked by cold branding the otoliths, and the resulting fry stocked into the lake in 1999. Peak counts of spawning kokanee were 5,100 fish on the shoreline and 9,700 fish in tributary streams; unusually high considering the low population in the lake. Opossum shrimp Mysis relicta declined in the southern two sections of the lake but increased in the northern end. Immature and mature shrimp (excluding young-of-the-year [YOY] shrimp) densities averaged 426 shrimp/m{sup 2}. The number of waterfowl using the lake in the winter of 1998-1999 increased from the previous three years to over 30,000 ducks, geese, and swans.
- Research Organization:
- Bonneville Power Administration, Portland, OR (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- 00004003; 1997BI98065
- OSTI ID:
- 776429
- Report Number(s):
- DOE/BP-98065-3; TRN: AH200120%%482
- Resource Relation:
- Other Information: PBD: 1 May 2000
- Country of Publication:
- United States
- Language:
- English
Similar Records
Kokanee Impacts Assessment and Monitoring of Lake Pend Oreille and Dworshak Reservoir, Idaho, 1994 Annual Report.
Effect of the Operation of Kerr and Hungry Horse Dams on the Reproductive Success of Kokanee in the Flathead System, 1987 Final Report.