Evidence of prevalent heat stress in Yukon River Chinook salmon

Canadian Journal Fisheries and Aquatic Sciences
By: , and 



Migrating adult Pacific salmon (Oncorhynchus spp.) are sensitive to warm water (>18 °C), with a range of consequences from decreased spawning success to early mortality. We examined the proportion of Yukon River Chinook salmon (O. tshawytscha) exhibiting evidence of heat stress to assess the potential that high temperatures contribute to freshwater adult mortality in a northern Pacific salmon population. Water temperatures greater than 18 °C have occurred almost annually in the Yukon River and correspond with low population abundance since the 1990s. Using gene transcription products and heat shock protein 70 biomarkers validated by field experiment, we identified heat stress in half of Chinook salmon examined (54%, n = 477) across three mainstem locations and three tributaries in 2016–2017. Biomarkers tracked wide variation in water temperature (14–23 °C) within a tributary. The proportion of salmon with heat stress differed between years at four of the six locations, with more prevalent heat stress in the warmer year. This work demonstrates that warming water temperatures are currently affecting northern populations of Pacific salmon.

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Publication type Article
Publication Subtype Journal Article
Title Evidence of prevalent heat stress in Yukon River Chinook salmon
Series title Canadian Journal Fisheries and Aquatic Sciences
DOI 10.1139/cjfas-2020-0209
Volume 77
Issue 12
Year Published 2020
Language English
Publisher Canadian Science Publishing
Contributing office(s) Alaska Science Center
Description 15 p.
First page 1878
Last page 1892
Country United States
State Alaska
Other Geospatial Yukon River
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