When Columbia River salmon reach the ocean, they may swim off in different directions than previously thought. that could require new thinking on how many fish are surviving their journey to the sea.
Up until now, most research counting juvenile salmon in the ocean has focused on those fish making a right-hand turn as they exited from the mouth of the Columbia River.
Fish heading toward the waters off shore from Washington, British Columbia, and Alaska got counted. Researchers didn’t know there could be salmon swimming south toward waters off the Oregon coast.
But a new study out of Pacific Northwest National Laboratory placed monitoring devices at the mouth of the Columbia River. The lab’s Geoff McMichael says researchers discovered that fish sometimes swam south or straight when the ocean currents pushed that direction. That means:
“It could be that juvenile survival is higher than has been reported," says McMichael.
McMichael says he didn’t expect to find large numbers of salmon swimming toward the shore of Oregon. He says it’s likely that these salmon eventually head north. But they may be going uncounted by swimming farther away from tracking devices north of the Columbia River.
Copyright 2013 Northwest Public Radio.