Influence of Didymosphenia geminata blooms on prey composition and associated diet and growth of Brown Trout

Transactions of the American Fisheries Society
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Abstract

We compared diet, stomach fullness, condition, and growth of Brown Trout Salmo trutta among streams with or without blooms of the benthic diatom Didymosphenia geminata in the Black Hills, South Dakota. In Rapid Creek, where D. geminata blooms covered ∼30% of the stream bottom, Brown Trout consumed fewer ephemeropterans (6–8% by weight) than individuals from two stream sections that have not had D. geminatablooms (Castle and Spearfish creeks; 13–39% by weight). In contrast, dipterans (primarily Chironomidae) represented a larger percentage of Brown Trout diets from Rapid Creek (D. geminata blooms present; 16–28% dry weight) compared with diets of trout from streams without D. geminata blooms (6–19% dry weight). Diets of small Brown Trout (100–199 mm TL) reflected the invertebrate species composition in benthic stream samples; in Rapid Creek, ephemeropterans were less abundant whereas dipterans were more abundant than in streams without D. geminata blooms. Stomach fullness and condition of Brown Trout from Rapid Creek were generally greater than those of Brown Trout from other populations. Linkages among invertebrate availability, diet composition, and condition of Brown Trout support the hypothesis that changes in invertebrate assemblages associated with D. geminata (i.e., more Chironomidae) could be contributing to high recruitment success for small Brown Trout in Rapid Creek.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Influence of Didymosphenia geminata blooms on prey composition and associated diet and growth of Brown Trout
Series title Transactions of the American Fisheries Society
DOI 10.1080/00028487.2015.1111255
Volume 145
Issue 1
Year Published 2016
Language English
Publisher Taylor & Francis
Contributing office(s) Coop Res Unit Leetown
Description 11 p.
First page 195
Last page 205