Climate change threatens Chinook salmon throughout their life cycle

Widespread declines in Atlantic and Pacific salmon have tracked recent climate changes, but managers still lack quantitative projections of the viability of any individual population in response to future climate change. This study assembled a vast database of survival and other data for eight wild populations of threatened Chinook salmon. Climate impacts at all life stages were evaluated, and future trajectories were modeled using global climate model projections. Populations rapidly declined in response to increasing sea surface temperatures and other factors. Strong density dependence limited the number of salmon that survived early life stages, suggesting a potentially efficacious target for conservation effort. Dramatic increases in smolt survival are needed to overcome the negative impacts of climate change.

Lisa G. Crozier, Brian J. Burke, Brandon E. Chasco, Daniel L. Widener, Richard W. Zabel