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Dahle, S.P. and J.T. Hatch. 2002. Gauging the threat of predation on the Topeka shiner (Notropis topeka)in Minnesota. Final report submitted to the Natural Heritage and Nongame Research Program, Minnesota Department of Natural Resources. 13 pp.
Introduction:
The Topeka shiner (Notropis topeka) is a small, stout minnow that inhabits slow-flowing habitats of headwater streams in the central prairie regions of the United States. In Minnesota, this species exists only in the Missouri River drainage, located in the southwestern corner of the state. Topeka shiners have relatively stable populations in Minnesota; however, their distribution and abundance have greatly declined over most of their range during this century, leading to their listing as federally endangered. Although habitat destruction and degradation are thought to be the primary causes for this decline, predation by introduced piscivorous species (particularly largemouth bass, Micropterus salmoides), following the construction of impoundments in streams containing Topeka shiners, has also been implicated. There have been no studies on the impacts of predation on the Topeka shiner, thus the significance of this threat is currently unknown. The purpose of this study was to determine which syntopic fishes prey on Topeka shiners in Minnesota and to gauge the impact of such predation by means of predator gut content analysis.