Changes in abundance and distribution of benthic macroinvertebrates after introduction ofcutthroat trout into a previously fishless lake

Document Type

Article

Journal/Book Title/Conference

Transactions of the American Fisheries Society

Volume

119

Publication Date

1990

Keywords

benthic, macroinvertebrates, cutthroat, trout

First Page

1010

Last Page

1021

Abstract

Densities of dominant macroinvertebrates declined in profundal and pelagic regions but not in littoral regions of Lake Lenore, Washington, after introduction of cutthroat trout Oncorhynchus clarki, Chaoborus flavicans, Hyalella azteca, and Callibaetis sp. composed over 90% of cutthroat trout diets, and these prey taxa showed the greatest response to the introduction. Although cutthroat trout selectively consumed larger individuals of these taxa and reduced mean length of prey in autumn populations, no change in size distribution of overwintering individuals was apparent 6 years after the fish were introduced. Reported changes in spatial distribution of these prey support the hypothesis that prey refuge space in littoral regions buffers prey populations from the direct effects of cutthroat trout predators.

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