CORVALLIS - Giving migrating spring chinook salmon a little more "fin room" during barge trips around Columbia River dams might reduce their stress and boost their health, according to Oregon State University researchers Larry Davis and Carl Schreck.
The U.S. Army Corps of Engineers barges thousands of juvenile fish every day during the spring chinook salmon runs in April and May. Barging is one of the ways in which the Corps is attempting to boost salmon runs without having to dismantle or bypass the dams that are believed to be among the possible causes for the threatened status of several species of Columbia River salmon.
While neither for nor against barging, Davis and Schreck have been studying the effects it has on migratory fish. Their work suggests that the cramped quarters for fish aboard the 25,000-gallon capacity barges increase the fish's stress. Davis said that equates to about three or four fish per gallon.
Putting about half that many fish in the barge appears to reduce stress, which is measured via indicators in the blood. Reducing stress is a goal, since stress appears to leave the fish more vulnerable to various diseases, which may weaken the fish during the period when they are adjusting to the salt water of the Pacific Ocean.
But increasing the number of barging runs could mean spending more money.
During the spring coho salmon runs on the Columbia in April and May, the Corps takes a trip around each dam every day, at a cost of about $15,000 a trip. That is small change compared to the approximately $435 million a year the Bonneville Power Administration loses in revenue in its efforts to increase salmon runs by spilling water over dams. That water is lost money, since it would generate electricity if it passed through the dam's turbines.
Since the dams provide inexpensive hydropower to the Northwest, utility companies, industries such as the power-dependent aluminum industry, and the farmers who depend on irrigation all want to see the dams stay in place, with barging as a tool to preserve or enhance fish runs.
Research into how fish respond to barging, as well as how they respond to passing through dams will continue this April, when the spring chinook run begins.
"Our goal is to find ways to improve the health and survival of young salmon as they travel to the ocean, whether it be in the river or inside a barge," said Davis.