State of the Canadian Pacific salmon: Responses to changing climate and habitats

Sue C.H. Grant, Bronwyn L. MacDonald, Mark L. Winston

Abstract

At Fisheries and Oceans Canada’s first State of the Salmon meeting in 2018, our scientists concluded that Canadian Pacific salmon and their ecosystems are already responding to climate change. Northeast Pacific Ocean warming trends and marine heatwaves like “The Blob” are affecting ocean food webs. British Columbia and Yukon air and water temperatures are increasing and precipitation patterns are changing, altering freshwater habitats. The effects of climate change in freshwater are compounded by natural and human-caused landscape change, which can lead to differences in hydrology, and increases in sediment loads and frequencies of landslides. These marine and freshwater ecosystem changes are impacting Pacific salmon at every stage of their life-cycle.

Some general patterns in Canadian Pacific salmon abundances are emerging, concurrent with climate and habitat changes. Chinook numbers are declining throughout their BC and Yukon range, and sockeye and coho numbers are declining, most notably at southern latitudes. Salmon that spend less time in freshwater, like pink, chum, river-type sockeye, and ocean-type Chinook, are generally not exhibiting long-term declines. These recent observations suggest that not all salmon are equally vulnerable to climate and habitat change.

Improving information on salmon vulnerability to changing climate and habitats will help ensure our fisheries management, salmon recovery, and habitat restoration actions are aligned to future salmon production and biodiversity. To accomplish this, we must integrate and develop new research across disciplines and organizations. One mechanism to improve integration of salmon-ecosystem science across organizations is the formation of a Pacific Salmon-Ecosystem Climate Consortium, which has been recently initiated by our State of the Salmon Program.

Related links

• E-book: State of the Canadian Pacific salmon: Responses to changing climate and habitats