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Low productivity of Chinook salmon strongly correlates with high summer stream discharge in two Alaskan rivers in the Yukon drainage.

Low productivity of Chinook salmon strongly correlates with high summer stream discharge in two Alaskan rivers in the Yukon drainage.

Authors :
Neuswanger, Jason R.
Wipfli, Mark S.
Evenson, Matthew J.
Hughes, Nicholas F.
Rosenberger, Amanda E.
Jonsson, Bror
Source :
Canadian Journal of Fisheries & Aquatic Sciences. Aug2015, Vol. 72 Issue 8, p1125-1137. 13p. 4 Charts, 7 Graphs.
Publication Year :
2015

Abstract

Yukon River Chinook salmon ( Oncorhynchus tshawytscha) populations are declining for unknown reasons, creating hardship for thousands of stakeholders in subsistence and commercial fisheries. An informed response to this crisis requires understanding the major sources of variation in Chinook salmon productivity. However, simple stock-recruitment models leave much of the variation in this system's productivity unexplained. We tested adding environmental predictors to stock-recruitment models for two Yukon drainage spawning streams in interior Alaska - the Chena and Salcha rivers. Low productivity was strongly associated with high stream discharge during the summer of freshwater residency for young-of-the-year Chinook salmon. This association was more consistent with the hypothesis that sustained high discharge negatively affects foraging conditions than with acute mortality during floods. Productivity may have also been reduced in years when incubating eggs experienced major floods or cold summers and falls. These freshwater effects - especially density dependence and high discharge - helped explain population declines in both rivers. They are plausible as contributors to the decline of Chinook salmon throughout the Yukon River drainage. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
0706652X
Volume :
72
Issue :
8
Database :
Academic Search Index
Journal :
Canadian Journal of Fisheries & Aquatic Sciences
Publication Type :
Academic Journal
Accession number :
108561286
Full Text :
https://doi.org/10.1139/cjfas-2014-0498