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Crayfish (Orconectes virilis) feeding on young lake trout (Salvelinus namaycush): effect of rock size

Journal of Freshwater Ecology

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Abstract

In laboratory studies, we quantified predation rates of crayfish (Orconectes virilis) on the eggs and sac fry of lake trout (Salvelinus namaycush) and a surrogate species, rainbow trout (Oncorhynchus mykiss), dispersed among different sized substrates (bare bottom, gravel, cobble, large rocks). Predation was most severe when no rocks were present. Feeding rate then decreased as the substrate changed from large rocks to cobble to gravel. Crayfish predation rate did not change with prey type -- rainbow trout and lake trout eggs or sac fry. Crayfish foraging in large tanks containing cobble averaged about two eggs or sac fry per day. In most instances, crayfish would have little impact on lake trout egg survival. Only in lake trout spawning grounds with relatively low egg densities, large crayfish populations, and cobble or large rock substrate, would crayfish be expected to have some impact on lake trout egg survival.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Crayfish (Orconectes virilis) feeding on young lake trout (Salvelinus namaycush): effect of rock size
Series title:
Journal of Freshwater Ecology
Volume
6
Issue:
2
Year Published:
1991
Language:
English
Contributing office(s):
Great Lakes Science Center
Description:
p. 161-170
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Freshwater Ecology
First page:
161
Last page:
170
Number of Pages:
9