Climate change threatens Chinook salmon throughout their life cycle

Widespread declines in Atlantic and Pacific salmon (Salmo salar and Oncorhynchus spp.) have tracked recent climate changes, but managers still lack quantitative projections of the viability of any individual population in response to future climate change. To address this gap, we assembled a vast database of survival and other data for eight wild populations of threatened Chinook salmon (O. tshawytscha). For each population, we evaluated climate impacts at all life stages and modeled future trajectories forced by global climate model projections. Populations rapidly declined in response to increasing sea surface temperatures and other factors across diverse model assumptions and climate scenarios. Strong density dependence limited the number of salmon that survived early life stages, suggesting a potentially efficacious target for conservation effort. Other solutions require a better understanding of the factors that limit survival at sea. We conclude that dramatic increases in smolt survival are needed to overcome the negative impacts of climate change for this threatened species.

Automated summary

Widespread declines in Atlantic and Pacific salmon have been attributed to recent climate changes, with a lack of quantitative projections on the viability of individual populations. Research on threatened Chinook salmon populations showed rapid declines in response to increasing sea surface temperatures, highlighting the need for increased conservation efforts to improve smolt survival rates in order to overcome the negative impacts of climate change.