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Prey availability, consumption, and quality contribute to variation in growth of subyearling Chinook Salmon rearing in riverine and reservoir habitats

Transactions of the American Fisheries Society

By:
, , and
DOI: 10.1080/00028487.2013.839958

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Abstract

We examined prey availability, prey consumed, and diet energy content as sources of variation in growth of natural fall Chinook Salmon Oncorhynchus tshawytscha subyearlings rearing in riverine and reservoir habitats in the Snake River. Subyearlings in riverine habitat primarily consumed aquatic insects (e.g., Diptera, Ephemeroptera, Trichoptera), of which a high proportion was represented by adult, terrestrial forms. In the reservoir, subyearlings also consumed aquatic insects but also preyed heavily at times on nonnative lentic amphipods Corophium spp. and the mysid Neomysis mercedis, which were absent in riverine habitats. The availability of prey was typically much higher in the reservoir due to N. mercedis often composing over 90% of the biomass, but when this taxon was removed from consideration, biomass estimates were more often higher in the riverine habitat. Subyearling diets during 2009–2011were generally 17–40% higher in energy in the riverine habitat than in the reservoir. Observed growth in both length and weight were significantly higher in the riverine habitat than in the reservoir. Little is known about how temporal and spatial changes in the food web in large river landscapes influence populations of native anadromous fishes. Our results provide a glimpse of how the spread and establishment of nonnative prey species can reduce juvenile salmon growth in a large river impoundment, which in turn can affect migration timing and survival.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Prey availability, consumption, and quality contribute to variation in growth of subyearling Chinook Salmon rearing in riverine and reservoir habitats
Series title:
Transactions of the American Fisheries Society
DOI:
10.1080/00028487.2013.839958
Volume
143
Issue:
1
Year Published:
2014
Language:
English
Publisher:
Taylor & Francis
Contributing office(s):
Western Fisheries Research Center
Description:
11 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Transactions of the American Fisheries Society
First page:
219
Last page:
229
Country:
United States
State:
Washington
Other Geospatial:
Snake River