Details:

Journal Title:
PLOS ONE
Personal Author:
Daly, E. A.; Brodeur, R. D.;
Daly, E. A.; Brodeur, R. D.; Less -
NOAA Program & Office:
CIMRS (Cooperative Institute for Marine Resources Studies); NMFS (National Marine Fisheries Service); NWFSC (Northwest Fisheries Science Center);
CIMRS (Cooperative Institute for Marine Resources Studies); NMFS (National Marine Fisheries Service); NWFSC (Northwest Fisheries Science Center); Less -
Description:
The trophic habits, size and condition of yearling Chinook salmon (Oncorhynchus tshawytscha) caught early in their marine residence were examined during 19 survey years (1981-1985; 1998-2011). Juvenile salmon consumed distinct highly piscivorous diets in cold and warm ocean regimes with major differences between ocean regimes driven by changes in consumption of juvenile rockfishes, followed by several other fish prey, adult euphausiids and decapod larvae. Notable, Chinook salmon consumed 30% more food in the warm versus cold ocean regime in both May and June. Additionally, there were about 30% fewer empty stomachs in the warm ocean regime in May, and 10% fewer in warm June periods. The total prey energy density consumed during the warmer ocean regime was also significantly higher than in cold. Chinook salmon had lower condition factor and were smaller in fork length during the warm ocean regime, and were longer and heavier for their size during the cold ocean regime. The significant increase in foraging during the warm ocean regime occurred concurrently with lower available prey biomass. Adult return rates of juvenile Chinook salmon that entered the ocean during a warm ocean regime were lower. Notably, our long term data set contradicts the long held assertion that juvenile salmon eat less in a warm ocean regime when low growth and survival is observed, and when available prey are reduced. Comparing diet changes between decades under variable ocean conditions may assist us in understanding the effects of projected warming ocean regimes on juvenile Chinook salmon and their survival in the ocean environment. Bioenergetically, the salmon appear to require more food resources during warm ocean regimes.
Keywords:
[+]
California Current
Chinook Salmon
Climatic Changes
Coho Salmon
Food Consumption
Marine Biodiversity
Pacific Salmon
Regions Of Freshwater Influence
Science
Sockeye Salmon
Spring
Technology
Variability

Source:
PLOS ONE. 2015; 10(12): e0144066.
DOI:
https://doi.org/10.1371/journal.pone.0144066
Pubmed Central ID:
PMC4682959
Document Type:
Journal Article;
Place as Subject:
Columbia River Watershed; California, Northern; United States;
Columbia River Watershed; California, Northern; United States; Less -
Rights Information:
CC BY
Compliance:
PMC
Main Document Checksum:
[+]
urn:sha256:9f687685113c1fa14eec5ce030a934c893170fd959c29c8b0a666274021ff6b6
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