Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 5748
Title: Competitive differences between newly emerged offspring of captively reared and wild coho salmon
Author: B. A. Berejikian, E. P. Tezak, S. L. Schroder, Thomas A. Flagg, C. M. Knudsen
Publication Year: 1999
Journal: Transactions of the American Fisheries Society
Volume: 128
Issue: 5
Pages: 832-839

We investigated competition among newly emerged fry from captive-reared and wild female coho salmon Oncorhynchus kisutch by conducting dominance challenges and growth and survival experiments in laboratory stream channels.  Newly emerged fry from captive-reared females won a significant majority (72.7%) of dyadic dominance challenges against fry from wild females.  In a growth and survival experiment conducted from emergence to 30 d post-emergence, fewer captive brood fry died of apparent starvation when food was limited than wild fry, further suggesting a competitive advantage for the captive brood fry.  All fry used in the study were paternal half-sibs, so observed differences between captive brood and wild fry were attributed to the maternal parent.  We hypothesize that fry coloration resulting from differences in egg color between wild and captive-reared females may have influenced the observed competitive asymmetries.  If so, such differences might be ameliorated by changes in husbandry practices such as providing more natural diets.

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