RICHLAND, Wash. - Psychology normally isn't associated with fisheries biology, but the behavior of fish could be an important factor in restoring endangered salmon stocks in the Columbia and Snake rivers.

Scientists at the Department of Energy's Pacific Northwest National Laboratory have developed tools to study how fish behave and to evaluate fish bypass systems at dams. The scientists coupled a multibeam sonar tool with an interactive computer animation program to track juvenile fish as they approach a prototype surface flow bypass recently installed at Bonneville Dam on the Columbia River between Washington and Oregon.

The multibeam sonar tool, called Dual-Head Multibeam Sonar, is a modification of a hydroacoustic device commonly used to map the bottom of oceans. The dual-head sonar nonintrusively tracks a fish's swimming direction and velocity over a large volume of water. Information collected by the multibeam sonar tool is transferred to computer software designed by Pacific Northwest. This software, called MTrack, tracks individual fish and allows for creation of a three-dimensional animation of what took place underwater.

"This is a very sophisticated system," said Robert L. Johnson, Pacific Northwest principal investigator. "These tools allow us to see fish movement more completely and take us one step closer to understanding how fish behave near these test facilities."

The U.S. Army Corps of Engineers, which built and operates Bonneville Dam, is attempting to find the best combination of bypass entrance dimensions, river velocity and flow to allow for safer downstream passage of juvenile salmon. Results from Pacific Northwest's study could be helpful in designing future surface flow bypasses, if that option is pursued as an alternative to passage through turbines.

Using the sonar tool, Pacific Northwest scientists tracked about 15,000 juvenile salmon as they approached the bypass at Bo
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Contact: Staci West
staci.west@pnl.gov
509-372-6313
DOE/Pacific Northwest National Laboratory
9-Feb-1999