A new University of Alaska-led study provides the first evidence that declines in many of Alaska’s chinook salmon populations can be attributed in part to climate-driven changes in their freshwater habitats.
Alaska chinook salmon runs have decreased during the past decade, leading to fisheries closures and prolonged economic and cultural impacts to local communities. With Alaska’s climate warming twice as fast as the global average and experiencing changes in precipitation and streamflow, the research team set out to understand if changing conditions in fresh water — where salmon spawn and rear — played a role in recent declines of chinook populations in the Cook Inlet basin of Southcentral Alaska.
The study examined historic chinook populations and modeled environmental conditions to estimate how stream conditions affected salmon productivity from 1980 to 2009. By using fisheries catch and spawning abundance data collected by the Alaska Department of Fish and Game, along with stream temperature data collected by Cook Inletkeeper, researchers were able to investigate how freshwater habitat conditions varied for 15 different chinook populations.