Scientists target salmon puzzle
Ocean devices will track habits
Scientists hope to unravel one of the great mysteries surrounding Northwest salmon by installing a network of sophisticated acoustic receivers off the coast to track fish as they journey thousands of miles through the Pacific Ocean.
The question: Where do they go and what do they do during the two or three years they spend in the ocean before returning to freshwater rivers and streams to spawn?
Eventually, the network could include 2,000 listening devices at 30 locations, stretching from Baja California to the Bering Sea, and it could track not only salmon but also sharks, rockfish, sturgeon and other fish and marine mammals up to and including blue whales.
Already, 200 receivers have been installed in Puget Sound – including at the Tacoma Narrows and the Hood Canal Bridge – to monitor South Sound coho salmon; steelhead from the Nisqually, Puyallup and Green rivers; and bull trout, sharks and Pacific squid.
They tracked a green sturgeon from Oregon and California’s Klamath River that was implanted with a transmitter several years ago. They’ve also tracked seven-gill sharks from Willapa Bay.
“I was studying a single juvenile bull trout in a single stream 15 years ago and thought that was cool,� said Fred Goetz, a fish biologist with the U.S. Army Corps of Engineers. “Now we are following fish all over Puget Sound and all the way to Alaska. My vision of the world has exploded.�
For now, much of the emphasis is on salmon. While scientists are starting to understand the effects of stream flows, dams and habitat on salmon, they know next to nothing when it comes to the time they spend in the ocean.
An earlier federal plan for protecting salmon said ocean survival was the “greatest uncertainty� in their life cycle and that ocean conditions could dwarf other factors affecting endangered and threatened runs.
“It’s a big black box,� said David Welch, a Canadian marine biologist whose company, Kintama Research, is spearheading the effort to install an ocean tracking system.
Welch’s three-year, $4.5 million plan will involve salmon from the Columbia and Snake rivers, Puget Sound and British Columbia. A smaller-scale demonstration program over the past two years has shown the tracking system will work, he said.
The network will be financed by the Bonneville Power Administration, several private foundations and Canadian fisheries agencies.
Continue reading this story from the Seattle Times:
Science targets salmon puzzle
