Lake Roosevelt Fisheries Monitoring Program; Lake Roosevelt Fisheries and Limnological Research; 1994 Annual Report.

Technical Report · Thu Aug 01 04:00:00 EDT 1996

DOI:https://doi.org/10.2172/395675· OSTI ID:395675

Tilson, Mary Beth ^[1]; Underwood, Keith D; Shields, John ^[2]

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1. Eastern Washington University, Upper Columbia United Tribes Fisheries Research Center, Cheney, WA
2. Spokane Tribe of Indians, Wellpinit, WA

This project began collecting biological data from Lake Roosevelt starting in 1991, with a long term goal of developing a computer model which accurately predicts biological responses to reservoir operations as part of the System Operation Review Program. In conjunction with the Lake Roosevelt Monitoring Project, this study collected limnological, reservoir operation, zooplankton, creel, net-pen rainbow trout and kokanee tagging data in 1994. Results obtained from current and past years data allow for the quantification of impacts to lake limnology, zooplankton, fish species and fisherman caused by reservoir drawdowns and low water retention times. in Lake Roosevelt, reservoir operations influence lake morphology as well as habitat availability for fish and their food. Lake elevations reached a yearly low of 1,263.90 feet above sea level in April and a yearly high of 1,288.50 feet in October. Lake Roosevelt experienced a peak in Daphnia spp. densities during July and August including the peak density of nearly 9,000 organisms per m{sup 3}. High densities of zooplankton were found in the lower end of the reservoir which supports the hypothesis that flushing of reservoir water increases downstream plankton densities and biomass as well as increasing entrainment of fishes. In 1994, a total of 26,975 net-pen rainbow trout were tagged at locations throughout the reservoir. Anglers fishing in Lake Roosevelt or below returned 448 tags, of which 399 tags were from fish tagged in 1994. Trends in tag returns continue to indicate that entrainment of Lake Roosevelt net-pen fish are influenced by water retention times and release times. Creel surveys of Rufus Woods were conducted over a six month period in 1993 and seven months in 1994 to estimate entrainment loss of tagged fish, however no tags were observed. Harvest estimates for the creel period were 46, 0 and 55 fish for rainbow trout, kokanee and walleye in 1993 and 384, 5 and 4,856 fish per year respectively in 1994.

• Research Organization: Spokane Indian Tribe, Wellpinit, WA (United States)
• Sponsoring Organization: United States. Bonneville Power Administration.
• OSTI ID: 395675
• Report Number(s): DOE/BP-91819-14; ON: DE97000949
• Country of Publication: United States
• Language: English

Related Subjects

13 HYDRO ENERGY
54 ENVIRONMENTAL SCIENCES
AQUATIC ECOSYSTEMS
AQUATIC ORGANISMS
AVAILABILITY
BIOLOGICAL EFFECTS
BIOMASS
BONNEVILLE POWER ADMINISTRATION
COLUMBIA RIVER
COMPUTERS
DAPHNIA
ENTRAINMENT
FISHERIES
FISHES
FOOD
HABITAT
HYDROELECTRIC POWER PLANTS
LIMNOLOGY
MONITORING
MORPHOLOGY
PLANKTON
POPULATION DYNAMICS
RETENTION
SEA LEVEL
Salmon fisheries - Northwest
Pacific
TROUT
WATER
WATER RESERVOIRS
ZOOPLANKTON