In February and March 2022, research ships from the United States, Canada, and Russia will set out into one of the roughest oceans in the world to unravel a mystery: What determines whether salmon that migrate across the North Pacific come back alive?
Understanding Salmon and the Ocean
The time salmon spend in the ocean represents one of the most variable, but least understood stages in their life cycles. Recent marine heatwaves in the northern Pacific Ocean and Gulf of Alaska are believed to be factors in increased variability in survival rates of young salmon across the region. Under climate change, heatwaves like this are expected to increase in frequency, duration and intensity in the future. This makes learning more about salmon productivity all the more important now.
The ocean represents one of the most variable and least understood stages in the life cycle of salmon that have long supported the communities, culture, and economies around the Pacific Rim. Unusual conditions including a series of record marine heatwaves have warmed the northern Pacific Ocean and Gulf of Alaska over the last decade, making salmon survival even more unpredictable. Climate change may accelerate that trend.
Researchers currently have only a cursory understanding of which salmon use which sections of ocean and what limits their survival during their years at sea, the longest stage of their life cycle.
The two-month 2022 Pan-Pacific Winter High Seas Expedition reflects the most ambitious attempt to:
- Map how salmon and steelhead migrate through the ocean
- Determine what affects their returns to rivers around the Pacific Rim, including West Coast and Alaska rivers such as the Columbia, Fraser, Sacramento, Yukon, and Kuskokwim
Information collected will provide a foundation for assessing, forecasting and managing salmon into the future. It may also help to build resiliency for the species and the people who depend on them. It also provides critical insights that may help us protect Alaska salmon stocks and recover West Coast and steelhead stocks that may face increasing pressure from climate change.
Four Ships With One Common Goal
The four research vessels include the NOAA research ship Bell M. Shimada, Canadian Coast Guard research ship Sir John Franklin, and Russian vessels. They will fan out across thousands of kilometers in the north Pacific and Gulf of Alaska.
Research ships from different nations will each study salmon and collect samples over different sections of the North Pacific.
They will collect oceanographic measurements and samples up to 1,000 meters deep and deploy trawl nets to catch salmon and steelhead. They will also sample other marine life that provides prey for salmon or prey on salmon during their years at sea.
- Examine the genetics of salmon to determine their native rivers
- Measure hormones that control the growth and health of salmon to understand how they mature
- Look for environmental DNA, floating fragments of genetic code that can help understand what other species may be using the same waters without getting caught in the nets
- Gauge the presence of microplastics that have been increasingly recognized as one of the most ubiquitous pollutants on the globe
Follow the International Expedition
Weather and ocean conditions permitting, scientists will provide regular reports from the field of what they are finding and what it may mean to the future of Pacific salmon. The expedition builds on earlier salmon research voyages where scientists developed many of the techniques they will use.
Compared to surveys in 2019 and 2020 in the Gulf of Alaska, the water was colder and salmon and other fishes were farther south, suggesting a relatively narrow temperature range for some species.
Like 2019, the scientists on board also caught quite a few skinny chum salmon that had little to nothing in their stomachs. These are the survivors and suggest conditions were tough for chum.
Unlike prior years, the scientists caught very few coho salmon, which were the second most abundant species in 2019 and 2020.
The expedition is organized under the International Year of the Salmon. It is supported by the North Pacific Anadromous Fish Commission, North Pacific Research Board, NOAA Fisheries, Fisheries and Oceans Canada, Alaska Department of Fish and Game, and Washington Department of Fish and Wildlife.