OSU aids young salmon to safer commute down the Columbia
Alternative nesting sites lure hungry birds away from sea-bound fish
Young salmon and steelhead migrate down the Columbia River to the Pacific Ocean where they feed and grow. But to get there, they have to make it past hungry Caspian terns. An OSU study found that Caspian terns nesting on Rice Island in the Columbia River estuary gobbled up about 12 million of the ocean-bound youngsters per year, roughly 10 percent of the salmon and steelhead that made it to the estuary.
So with assistance from OSU, various management agencies developed new nesting habitat at East Sand Island near the mouth of the river where there's a wider variety of fish for terns to eat. It worked. The relocated terns – up to 10,000 breeding pairs – eat less than half as many juvenile salmonids as they did when they nested on Rice Island.
The Army Corps of Engineers then created more nesting sites by building islands in places that include Malheur Lake in Harney County and Summer and Crump lakes in Lake County, where they feed primarily on small tui chub, bullhead catfish and crappie. At the same time, nesting habitat on East Sand Island was reduced to encourage terns to nest elsewhere. Nearly 60 Caspian terns that had been banded at East Sand Island showed up at the islands in interior Oregon in 2013, suggesting that hundreds of Caspian terns have shifted their nesting sites from the Columbia River estuary to new islands in eastern Oregon nearly 250 miles away.
That's good news for the state's ocean and in-river fishing industry, which harvested nearly $7 million of salmon in 2012.
Find out more about OSU's work to relocate Caspian terns in a video and an article in Oregon's Agricultural Progress magazine.
Sources: Oregon Department of Fish and Wildlife; OSU seabird biologist Dan Roby; Oregon Department of Agriculture.