In early August, the Alaskan Department of Fish and Game announced it would be canceling the remainder of the sport and commercial fishing season for chinook (king) salmon, citing extremely low stocks, the High Country News reported last week.
The chinook stocks weren’t only low in the Gulf of Alaska; drastically lower numbers were seen off the coast of Washington and Oregon as well. And, in other states such as California, measures to help protect chinook have been enacted. Earlier this week, California Secretary for Natural Resources John Laird launched a program bringing together farmers, fishermen, and state and federal water and wildlife agencies to protect salmon habitats in the state. Besides Alaska, the rivers and tributaries in the Central Valley of California have been the second-most productive area for salmon in the country.
Scientists have linked the depletion in chinook numbers to climate change, including rising sea temperatures and the drought that has been plaguing California for years. As ocean water has gotten hotter and been fed less by rivers and streams that have dried up as a result of California’s drought, the waters have become emptier of nutrients such as photoplankton and zooplankton. As a result, smaller fish that feed on plankton died off. This has made it more difficult for the salmon to find food, and as a result they have died off as well, scientists have determined.
“The whole prey base got screwed up,” said Laurie Weitkamp, a fisheries biologist who specializes in salmon for the National Oceanic and Atmospheric Administration.
However, some experts are not ready to blame ocean temperature exclusively for the decline in numbers.
“We don’t know yet what the real effect of the [warming] was on chinook salmon,” Daniel Schindler, a fisheries professor at the University of Washington, said. “The warm conditions in the last few years are unprecedented. But it’s too early to tell if the poor returns this year are due to climate or not.”
