Abundance and Distribution of Walleye, Northern Squawfish and Smallmouth Bass in John Day Reservoir and Tailrace, 1983 Annual Report.

Technical Report · Mon Apr 01 04:00:00 EST 1985

DOI:https://doi.org/10.2172/5447558· OSTI ID:5447558

Nigro, Anthony A; Uremovich, Barry L; Elliott, John C ^[1]

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1. Oregon Department of Fish and Wildlife, Columbia River Section, John Day, OR

Walleye, northern squawfish and smallmouth bass abundances were estimated in portions of John Day Reservoir and tailrace using a multiple mark and recapture method. Sampling was conducted from March 28 to September 23, 1983, using gill nets, trap nets, boat electrofishing, angling and an angler survey. A total of 1808 walleye, 6423 northern squawfish and 974 small mouth bass were collected. Abundance was estimated using a modified Schnabel estimator. Discrete populations were defined according to observed movements of recaptured and radiotagged fish. Abundance estimates were corrected for angler harvest, size selectivity by gear and recruitment due to growth during sampling. In addition, the likelihood of biases resulting from differential mortality of marked fish and tag loss was examined. Abundances of walleye with fork lengths greater than 250 mm were estimated as 6877 below John Day Dam and 9,463 in the upper John Day pool. Extensive movements by walleye within pools were observed. Angler harvest of walleye between May 25 and September 6 was estimated as 527 in John Day tailrace and 465 in McNary tailrace. Abundances of northern squawfish with fork lengths greater than 250 mm were estimated to be 32,126 below John Day Dam, 10,841 forebay and 27,771 in upper John Day pool. The estimated number of northern squawfish in the McNary tailrace boat restricted zone after cessation of spill (July 2) was twice the estimated abundance during spill (March 28-July 1). Smallmouth bass abundance was estimated as 1087 below John Day Dam, 1501 in John Day forebay and 3,450 in upper John Day pool. 16 refs., 32 figs., 47 tabs.

• Research Organization: Oregon Dept. of Fish and Wildlife, Corvallis (USA)
• Sponsoring Organization: United States. Bonneville Power Administration.
• OSTI ID: 5447558
• Report Number(s): DOE/BP-35097-1; ON: DE85016233
• Country of Publication: United States
• Language: English

Related Subjects

520100* -- Environment
Aquatic-- Basic Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
ABUNDANCE
ANADROMOUS FISHES
ANIMALS
AQUATIC ORGANISMS
BASELINE ECOLOGY
COLUMBIA RIVER
DISTRIBUTION
ECOLOGY
FEDERAL REGION X
FISHES
Fish populations - John Day Reservior (Or. and Wash.)
NORTH AMERICA
OREGON
RIVERS
SAMPLING
SIZE
SPATIAL DISTRIBUTION
STREAMS
SURFACE WATERS
USA
VERTEBRATES
WASHINGTON
WATER RESERVOIRS