System-Wide Significance of Predation on Juvenile Salmonids in Columbia and Snake River Reservoirs : Annual Report of Research 1990.

Technical Report · Fri Mar 01 04:00:00 EST 1991

DOI:https://doi.org/10.2172/6058370· OSTI ID:6058370

Petersen, C J

The consumption rates of northern squawfish (Ptychocheilus oregonensis) preying upon juvenile salmonids were indexed in four reservoirs (Bonneville, The Dalles, John Day and McNary) of the lower Columbia River. During the spring and summer of 1990, over 2000 northern squawfish were collected from dam forebays, dam tailraces and mid-reservoir locations. Gut content data, predator weight and water temperature were used to compute a consumption index (CI) for northern squawfish. Juvenile salmonids were found in 435 of 1598 northern squawfish guts analyzed. Besides salmonids and other preyfish, crustaceans formed a significant portion of the diet. The CI of northern squawfish varied by season and location. At most locations, summer CI's of northern squawfish were higher than in the spring. Efforts to match sample collection with times of highest juvenile salmonid passage were successful except during July at The Dalles and Bonneville Reservoirs. Consumption indices were moderate to high at several locations even when passage was relatively low, suggesting salmonid predation rate by northern squawfish was not always a function of prey density. 19 refs., 5 figs., 12 tabs.

• Research Organization: US Fish and Wildlife Service
• Sponsoring Organization: US Bonneville Power Administration
• DOE Contract Number: AI79-90BP07096
• OSTI ID: 6058370
• Report Number(s): DOE/BP-07096-1; ON: DE91009784
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540310 -- Environment
Aquatic-- Basic Studies-- (1990-)
550100* -- Behavioral Biology
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AQUATIC ORGANISMS
BIOLOGICAL STRESS
BONNEVILLE POWER ADMINISTRATION
COLUMBIA RIVER
DOCUMENT TYPES
ENVIRONMENTAL IMPACTS
FISHES
JUVENILES
MORTALITY
NATIONAL ORGANIZATIONS
POPULATION DYNAMICS
PREDATOR-PREY INTERACTIONS
PROGRESS REPORT
RIVERS
SNAKE RIVER PLAIN
STREAMS
SURFACE WATERS
Salmonidae - Columbia River - Mortality
US DOE
US ORGANIZATIONS
VERTEBRATES