North American Journal of Fisheries Management 24:33–40, 2004 q Copyright by the American Fisheries Society 2004 Influence of Habitat Type on Food Supply, Selectivity, and Diet Overlap of Bonneville Cutthroat Trout and Nonnative
Abstract.—We collected invertebrate drift samples and stomach contents of native Bonneville cutthroat trout Oncorhynchus clarki utah and nonnative brook trout Salvelinus fontinalis in Beaver Creek, Idaho, during August 1995 to assess food availability and the potential for competition. Regardless of...
| Main Authors: | , , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.490.1673 http://www.nrmsc.usgs.gov/files/norock/products/04najfmbct.pdf |
| Summary: | Abstract.—We collected invertebrate drift samples and stomach contents of native Bonneville cutthroat trout Oncorhynchus clarki utah and nonnative brook trout Salvelinus fontinalis in Beaver Creek, Idaho, during August 1995 to assess food availability and the potential for competition. Regardless of whether samples came from beaver pond or from high-gradient or low-gradient reaches, aquatic Diptera numerically dominated drifting invertebrates by at least fivefold over all other categories captured in 1-h drift samples. Abundances and drift densities of drifting inver-tebrates were high in the three reach habitat types sampled: beaver pond (3,152 individuals; 18.9 invertebrates/m3), high-gradient reach (5,216 individuals; 26.5 invertebrates/m3), and low-gradient reach (4,908 individuals; 17.2 invertebrates/m3). Cutthroat trout consumed significantly more in-vertebrates per individual than did brook trout. However, there was no relationship between fish length and consumption. Diets of both brook and cutthroat trout were dominated by Diptera in beaver ponds and terrestrial invertebrates in the high-gradient reach. In the low-gradient reach, Diptera dominated brook trout diets, whereas both Diptera and terrestrial invertebrates dominated diets of cutthroat trout. Both trout species consistently selected terrestrial invertebrates and Tri-choptera in all reach types. Diet overlap between brook and cutthroat trout was 92 % in beaver |
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