Spatial, seasonal and diel distribution of fishes in a California reservoir dominated by native fishes

Bruce C. Vondracek; Donald M. Baltz; Larry R. Brown; Peter B. Moyle

doi:10.1016/0165-7836(89)90005-2

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Spatial, seasonal and diel distribution of fishes in a California reservoir dominated by native fishes

Bruce C. Vondracek·Donald M. Baltz·Larry R. Brown·Peter B. Moyle

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Abstract

During 21 months of sampling with various techniques, we captured 24 species of fish in Britton Reservoir. Nine species comprised over 96% of the number of fish captured and approximately 88% of the biomass. Five native non-game species accounted for over 77% of the catches. The native non-game fishes have maintained large populations in the reservoir despite continued introductions of non-native species. Two sources of non-native species exist. The first is the introduction of exotic species directly into the reservoir during fish-stocking programs. The second is the continuous movement of non-native fishes into the reservoir from large populations which reside in a major tributary of the reservoir. Factors responsible for the large number of native fishes are: management of the reservoir for hydroelectric generation; temperature regime; reservoir morphology. The fish community structure is stratified along two axes: upper basin/lower basin and inshore/offshore. Most of the 24 species were found inshore: 14 species were found offshore. Four of the native non-game fishes were most abundant in the upper basin: three introduced non-native fishes were most abundant in the lower basin of the reservoir. The offshore community was dynamic on a daily and seasonal basis.

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Bruce C. Vondracek, Donald M. Baltz, Larry R. Brown, Peter B. Moyle. 1989. Spatial, seasonal and diel distribution of fishes in a California reservoir dominated by native fishes. https://doi.org/10.1016/0165-7836(89)90005-2

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