大象传媒

While anglers are celebrating a strong start to the salmon season, a new 大象传媒 study warns coho salmon are under serious threat.

The research, published in the Canadian Journal of Fisheries and Aquatic Sciences, found that coho salmon populations in the north and central coast of B.C. have plummeted by more than a third in the last decade.

Marine heatwaves and overfishing are among the factors behind their sharp decline, according to researchers.

鈥淎larm bells should be ringing. Our findings support what First Nations have been saying for years 鈥� coho salmon populations are under serious threat,鈥� says lead author Kyle Wilson, assistant professor at 大象传媒鈥檚 School of Resource and Environmental Management.

鈥淯nless urgent steps are taken to address the decline, then we could be facing a damaging collapse in their population.鈥�

The looked at populations of coho salmon in 52 rivers along B.C.鈥檚 north and central coast and found that the number of spawners dropped 37 per cent in 2020 compared to averages between 2000-2015.

It also found that productivity 鈥� the number of offspring produced by spawners 鈥� collapsed for many coho populations during marine heatwaves at the end of the last decade.

A marine heatwave is when abnormally high ocean temperatures persist in a particular region for an extended period of time 鈥� weeks, months or even years.

Higher ocean temperatures can harm marine wildlife, reducing the amount of available food in marine ecosystems, increasing the metabolic demands of feeding salmon, and altering patterns of rainfall and river flow for juveniles.

鈥淪almon are typically considered cold water species,鈥� says Wilson.

鈥淗igher ocean temperatures mean coho salmon are dealing with heat stress and so need to eat more. But if they can鈥檛 find food because their prey are also being hit by the higher temperatures, then they鈥檙e potentially going to starve.鈥�

While B.C. anglers have welcomed positive returns of sockeye and pink salmon so far this year, coho migrate later into the winter, making them less visible and harder to study.

Coho salmon also face increased competition for food from pink salmon, whose numbers are at an all-time high in the North Pacific Ocean, in part due to industrial scale hatcheries.

Researchers assessed how commercial and recreational fisheries spanning Indigenous, Canadian and U.S. jurisdictions impede coho population recovery.

鈥淩educing the harvest from commercial and recreational fisheries, in both Alaskan and Canadian waters, would provide coho salmon with the time and space that they need to adapt to climatic changes,鈥� says Wilson.

Wilson says the study is timely as negotiations between Canada and the U.S. over the Pacific Salmon Treaty, which is meant to prevent overfishing and protect salmon stocks, are due to pick up next year.

鈥淒ecision makers need to sit-up and take note of the situation,鈥� says Wilson. 鈥淏ut it鈥檚 going to need Indigenous, Canadian and American fishery managers to work together. We need management processes that can adapt quickly to changing conditions.

鈥淭he good news is that coho are resilient. They have been in this position before and their numbers have recovered rapidly when the right levers have been pulled and environmental conditions are favourable.鈥�

The study was a collaboration between Central Coast First Nations, 大象传媒, Wild Salmon Center and Fisheries and Oceans Canada.

Available 大象传媒 Experts

KYLE WILSON, assistant professor, School of Resource and Environmental Management | kl_wilson@sfu.ca

Contact

SAM SMITH, 大象传媒 Communication & Marketing
236.880.3297 | samuel_smith@sfu.ca

SIMON FRASER UNIVERSITY
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778.782.3210

About 大象传媒

大象传媒 is a leading research university, advancing an inclusive and sustainable future. Over the past 60 years, 大象传媒 has been recognized among the top universities worldwide in providing a world-class education and working with communities and partners to develop and share knowledge for deeper understanding and meaningful impact. Committed to excellence in everything we do, 大象传媒 fosters innovation to address global challenges and continues to build a welcoming, inclusive community where everyone feels a sense of belonging. With campuses in British Columbia鈥檚 three largest cities鈥擝urnaby, Surrey and Vancouver鈥敶笙蟠� has ten faculties that deliver 368 undergraduate degree programs and 149 graduate degree programs for more than 37,000 students each year. The university boasts more than 200,000 alumni residing in 145+ countries.