|Title:||Food of fishes in the Columbia River estuary|
|Author/Editor:||Robert L. Emmett, William D. Muir, Teresa L. Clocksin, Theodore H. Blahm|
|Institution:||Report of the Northwest and Alaska Fisheries Center|
The diets of 25 fish species collected in demersal, pelagic, and intertidal habitats of the Columbia River estuary (Washington and Oregon) were studied from February 1980 through January 1981. Distinct feeding guilds (fishes with similar diets) were identifiable in every season. Guilds were represented by more species in spring and summer because of the presence of anadromous species and probably also in response to abundant prey. Some fishes showed large seasonal variations in diet. The kinds of prey consumed appeared to be determined by their seasonal abundances and availability. The limited food resource partitioning indicates little competition and may be a result of abundant but species-poor prey resources. Widely fluctuating estuarine physical conditions may also play an important role .