Feeding bionomics of juvenile chinook salmon relative to thermal discharges in the central Columbia River
Juvenile chinook salmon (Oncorhynchus tshawytscha) in the Hanford environs of the central Columbia River, Washington consumed almost entirely adult and larval stages of aquatic insects. The food organisms were dominated by midges (Diptera: Tendipedidae); by numbers, adult midges provided 64 and 58% of the diet and larval midges 17 and 18% of the diet, in 1968 and 1969, respectively. The families Hydropsychidae (Trichoptera), Notonectidae (Hemiptera) and Hypogastruridae (Collembola) were of secondary importance. Small fry fed almost exclusively on the small tendipedids. Over 95% of all food organisms originated within the river ecosystem. The distinctive features of food and feeding activity were fourfold: first, relatively few insect groups were utilized; second, the fish depended on drifting, floating, or swimming organisms; third, they visually selected living prey moving in or on the water; and fourth, they were habitat opportunists to a high degree. The 1969 data, were studied to reveal possible thermal effects of heated discharges from plutonium production reactors at Hanford on food and growth parameters. All data were characterized by considerable variation between and within stations. No discernable effects between coldwater and warmwater stations were revealed by analyses of: (1) groups of food organisms utilized, (2) food and feeding activity, (3) numbers of insects consumed, (4) seasonal increases in fish length, (5) fish length-weight relationships, (6) fish coefficients of condition, and (7) stomach biomass. The lack of detectable thermal effects was apparently due to the fact that the main effluent plumes discharge in midstream and the effluents are well mixed before reaching inshore feeding areas. The transient nature of fish groups at each station, influenced by changes in regulated river flows, and the availability of food organisms in the river drift were ecological factors affecting critical thermal evaluation in situ.
- Research Organization:
- Battelle Pacific Northwest Lab., Richland, WA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 10188605
- Report Number(s):
- BNWL-SA-3932; ON: DE95001319; TRN: 94:009353
- Resource Relation:
- Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
Similar Records
Food and feeding of juvenile chinook salmon in the central Columbia River in relation to thermal discharges and other environmental features
Preliminary biological measurement program in the Savannah River. Final report, 1 March-31 August 1982. Volume II
Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
SALMON
DIET
GROWTH
THERMAL POLLUTION
BIOLOGICAL EFFECTS
PLUTONIUM PRODUCTION REACTORS
ENVIRONMENTAL EFFECTS
COLUMBIA RIVER
HABITAT
HANFORD RESERVATION
053003
560200
CHEMICAL AND THERMAL EFFLUENTS
THERMAL EFFECTS