Lamprey Dams
7:02 am
Mon March 17, 2014

Swim, Lamprey, Swim!

An eel-like fish native to the Northwest can now more easily make it up the Columbia River. Managers at the Columbia’s McNary Dam have installed a new passage system for Pacific lamprey – the first of its kind for the toothy fish.

The Lamprey is a jawless fish which has a toothy, funnel-like mouth.
The Lamprey is a jawless fish which has a toothy, funnel-like mouth.
Credit USFWS Pacific

Pacific lamprey are an important cultural and dietary staple for Northwest tribes. Lamprey numbers have dropped dramatically in the past 25 years. No one is really sure why – but some fish biologists suspect difficulty swimming upstream is partly to blame.

A recent study showed lamprey had trouble making it past the McNary Dam on the Columbia River’s Washington-Oregon border.

Now, dam managers have built a new fish passage system 30 feet below the Columbia River’s surface.

Steve Juhnke is a fisheries biologist with the U.S. Army Corps of Engineers. He says lamprey don’t do well in traditional fish ladders designed for salmon. They prefer slow-flowing water near the riverbed.

"It's thought that mostly lamprey migrate closer to the bottom as they approach the hydroelectric facilities," said Juhnke.

Juhnke says if this system works well, other dams could install a similar design.

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