Scientists Take Aim at Mystery of Declining Salish Sea Salmon

Aug 21, 2013

Survival rates for salmon and steelhead in Puget Sound have plunged since the 1970s, and a big new international study is aiming to figure out why.

For salmon and steelhead in the Salish Sea, which consists of Puget Sound and neighboring Canadian waters, life gets pretty hard as soon as they hit saltwater. Less than one percent of king salmon and steelhead survive into adulthood, a fraction of what it was 40 years ago. Now scientists are launching a coordinated effort to solve this biological mystery.

Washington Department of Fish and Wildlife Director Phil Anderson said millions of dollars have been spent trying to save habitat, restrict fishing and modernize hatcheries, but none of it has slowed the decline.

“We have to figure out what the cause is of the high mortality rates, or our investments in the rest of these areas will not bring results. That is why I think this is the most important work we could do right now,” Anderson said, speaking at a launch event at the Seattle Aquarium.

Resource management agencies like Anderson’s in both the U.S. and Canada, along with non-profits and tribes, are locking arms as part of the Salish Sea Marine Survival Project.

They’re planning to do detailed surveys of what happens to young fish as they enter the sea. They say scientists know much less about what’s happening in that phase of the fish’s lives, compared with the freshwater period.

Researchers say the reasons for the decline are mysterious, but may involve lack of food, toxic pollutants, harmful algal blooms and more predators. Organizers expect the study to cost about $10 million over the next five years, with Washington State providing $800,000 to get it underway.