Salmon decline impacted by “squeeze” of combined river and sea stressors
Study traces 40 years of change on Vancouver Island river-to-sea salmon and trout pathway
IMAGE: COHO SMOLT. view more
CREDIT: JULIAN GAN
Researchers from Simon Fraser University’s Salmon Watershed Lab have found that recent declines of Pacific salmon and trout are associated with 40 years of changes in their combined marine and freshwater ecosystems.
Led by lab researcher Kyle Wilson, the study found that stressors in both environments combine to impact fish resiliency. “It’s not just the ocean that is driving declines,” says Wilson, a former SFU Banting postdoctoral fellow. “The combination of marine and freshwater stressors effectively ‘squeezes’ some salmon populations by lowering survival in both the river and the sea.”
The study, published today in the journal Global Change Biology, traces declining numbers in five salmon species found in the Keogh River near Port Hardy on Vancouver Island.
The declines were found to coincide with combinations of stressful environmental changes including fluctuating ocean climate, increases in coastal seals and other competing salmon, warmer water temperatures, and increased watershed logging.
CAPTION
Keogh sampling.
CREDIT
Colin BaileyWilson says the study findings can help inform policies such as the federal government’s recent Pacific Salmon Strategy Initiative (PSSI) which will allocate $647.1 million to a wide variety of conservation and scientific efforts to help recover salmon.
CAPTION
Morice Steelhead.
CREDIT
Jonathan Moore
The research was carried out by Wilson and SFU biology professor Jonathan Moore, along with lab researchers Colin Bailey and Provincial collaborator Trevor Davies. The study’s research funders include the Habitat Trust Conservation Fund.
CAPTION
Keogh e-fishing sampling 2020.
CREDIT
Sean Naman
JOURNAL
Global Change Biology
METHOD OF RESEARCH
Data/statistical analysis
SUBJECT OF RESEARCH
Animals
CAPTION
Keogh Steelhead.
CREDIT
Kyle Wilson
ARTICLE TITLE
Marine and freshwater regime changes impact a community of migratory Pacific salmonids in decline
ARTICLE PUBLICATION DATE
20-Oct-2021
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