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Individual condition and stream temperature influence early maturation of rainbow and steelhead trout, Oncorhynchus mykiss

Environmental Biology of Fishes

By:
, , , , and
DOI: 10.1007/s10641-011-9921-0

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Abstract

Alternative male phenotypes in salmonine fishes arise from individuals that mature as larger and older anadromous marine-migrants or as smaller and younger freshwater residents. To better understand the processes influencing the expression of these phenotypes we examined the influences of growth in length (fork length) and whole body lipid content in rainbow trout (Oncorhynchus mykiss). Fish were sampled from the John Day River basin in northeast Oregon where both anadromous ("steelhead") and freshwater resident rainbow trout coexist. Larger males with higher lipid levels had a greater probability of maturing as a resident at age-1+. Among males, 38% were maturing overall, and the odds ratios of the logistic model indicated that the probability of a male maturing early as a resident at age-1+ increased 49% (95% confidence interval (CI) = 23-81%) for every 5 mm increase in length and 33% (95% CI = 10-61%) for every 0. 5% increase in whole body lipid content. There was an inverse association between individual condition and water temperature as growth was greater in warmer streams while whole body lipid content was higher in cooler streams. Our results support predictions from life history theory and further suggest that relationships between individual condition, maturation, and environmental variables (e. g., water temperature) are shaped by complex developmental and evolutionary influences. ?? 2011 Springer Science+Business Media B.V.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Individual condition and stream temperature influence early maturation of rainbow and steelhead trout, Oncorhynchus mykiss
Series title:
Environmental Biology of Fishes
DOI:
10.1007/s10641-011-9921-0
Volume
93
Issue:
3
Year Published:
2012
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Environmental Biology of Fishes
First page:
343
Last page:
355
Number of Pages:
13