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Publication Date

2001

Keywords

Topeka shiner; Endangered species; Fish declines

Abstract

The Topeka shiner, Notropis topeka, is the first of Minnesota's native ichthyofauna to be classified as federally endangered. The species is in serious decline in Kansas, Missouri, Nebraska and Iowa but is far more common in Minnesota than once was thought. At present, it is known from 89 sites in 17 streams of the Missouri River Drainage. Topeka shiners are multiple-clutch spawning nest associates of sunfishes and reproduce over an eight- to ten-week period between late May and early August. Mean clutch size is 261 to 284. Longevity is three years. Males grow faster than females, reaching longer mean total lengths at age I and II. Topeka shiners feed on a large variety of food items from at least three trophic levels and function both as benthic and nektonic feeders. What makes Minnesota populations different from those to the south is their use of off-channel oxbows and excavated pools, which they use in conjunction with low-gradient, sediment-loaded streams. I hypothesize these habitats are crucial to the long-term survival of this species and conclude that maintaining these habitats should be a high priority in southwestern Minnesota.

First Page

39

Last Page

46

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