System-Wide Significance of Predation on Juvenile Salmonids in the Columbia and Snake River Reservoirs : Annual Report of Research 1991.

Technical Report · Tue Jan 01 04:00:00 EST 1991

DOI:https://doi.org/10.2172/7076789· OSTI ID:7076789

Shively, R S

We indexed consumption rates of northern squawfish (Ptychoch oregonensis) preying upon juvenile salmonids in four lower Snake River reservoirs. Stomach contents were also collected from smallmouth bass (Micropterus dolomieui), channel catfish (Ictaluris gunctatus), and walleye (Stizostedion vitreum). Northern squawfish digestive tracts were analyzed and the overall diet (% weight) was dominated by fish and crustaceans. Examination of stomach contents smallmouth bass showed that crustaceans (primarily crayfish) dominated their diets. Overall, the consumption rate of juvenile salmonids by smallmouth bass was low. The northern squawfish consumption index (CI) at Snake River locations ranged from zero at all mid-reservoir locations to 1.2 at Lower Granite forebay. In John Day Reservoir, CI values ranged from 0.5 to 1.9 in May and from 0.9 to 3.0 in July. Consumption index values were highest in forebay and tailrace areas, and were slightly higher in BRZs than in non-restricted zones.

• Research Organization: US Fish and Wildlife Service
• Sponsoring Organization: US Bonneville Power Administration
• DOE Contract Number: AI79-90BP07096
• OSTI ID: 7076789
• Report Number(s): DOE/BP-07096-2; ON: DE92040931
• Country of Publication: United States
• Language: English

Related Subjects

13 HYDRO ENERGY
130600 -- Hydro Energy-- Environmental Aspects
54 ENVIRONMENTAL SCIENCES
540210* -- Environment
Terrestrial-- Basic Studies-- (1990-)
ANADROMOUS FISHES
ANIMAL GROWTH
ANIMALS
AQUATIC ORGANISMS
BASELINE ECOLOGY
DOCUMENT TYPES
ECOLOGY
FISHES
GROWTH
JUVENILES
PREDATOR-PREY INTERACTIONS
PROGRESS REPORT
SALMON
SURFACE WATERS
Salmonidae - Columbia River - Mortality
VERTEBRATES
WATER RESERVOIRS