8133

• UCREFRP Catalog Number: 8133
• Author: Collins, K. and D. K. Shiozawa.
• Title: The Effects of Fish Predation on Backwater Invertebrate Communities of the Green River, Utah\
• USFW Year: 1996.
• Copyright Material: NO

post-larval ( < 70 mm) squawfish that inhabit backwaters may be experiencing high mortality
rates (Karp and Tyus 1990). Since juvenile squawfish are piscivorous they should benefit
from high densities of non-native minnows, but post-larval squawfish have a diet mostly of
chironomid larvae, similar to many of the non-native backwater species (Grabowski and
Hiebert 1989). Our results, indicate that backwater fishes may significantly impact their
resources. The direct consequences of fish predation can also have indirect effects on other
invertebrate groups through cascading trophic interactions. This depletion of food resources
by the fish community may have negative repercussions for native fish species such the
Colorado squawfish. Additional research would be necessary to determine if this is the case.
LITERATURE CITED
Allan, J. D. 1982. The effects of reduction in trout density on the invertebrate
community of a mountain stream. Ecology 63:1444-1455.
Allan, J. D. 1983. Predator-prey relationships in streams. Pages 191-229 in J. R. Barnes
and G. W. Minshall, editors. Stream ecology: application and testing of general
ecological theory. Plenum, New York, New York, USA.
Angermeier, P. L. 1985. Spatio-temporal patterns of foraging success for fishes in an Illinois
stream. American Midland Naturalist 114:342-359.
Brooks, J. L.., and S. I. Dodson. 1965. Predation, body size, and composition of
plankton. Science 150:28-35.
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