Density-dependence at sea for coho salmon (Oncorhynchus kisutch)

Canadian Journal of Fisheries and Aquatic Sciences
By: , and 

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Abstract

The success of expanded salmon hatchery programs will depend strongly on the degree of density-induced diminishing returns per smolt released. Several authors have addressed the question of density-dependent mortality at sea in coho salmon (Oncorhynchus kisutch), but have come to conflicting conclusions. We believe there are compelling reasons to reinvestigate the data, and have done so for public hatchery fish, using a variety of approaches. The results provide evidence that survival of these public hatchery fish is negatively affected, directly by the number of public hatchery smolts and indirectly by the number of private hatchery smolts. These results are weak, statistically, and should be considered primarily as a caution to those who, on the basis of other published work, believe that density-dependence does not exist. The results reported here also re-emphasize the often overlooked point that inferences drawn from data are strongly biased by investigators' views of how the systems of interest work and by the statistical assumptions they make preparatory to the analysis of those data.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Density-dependence at sea for coho salmon (Oncorhynchus kisutch)
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/f90-200
Volume 47
Year Published 1990
Language English
Publisher NRC Research Press
Contributing office(s) Western Fisheries Research Center
Description 8 p.
First page 1765
Last page 1772