Oregon Public Broadcasting

Federal fishery biologists are engaged in a high seas hunt to locate prized Columbia River steelhead.

Scientists want to know where these threatened fish disappear to while they mature in the Pacific Ocean.  To help the search, the researchers have enlisted some unusual -- and furry -- assistants.  Tom Banse explains.

Somewhere out there in the great wide North Pacific are 100 special steelhead.  In the spring, the oceangoing trout were implanted with little electronic tags at the mouth of the Columbia River. 

A juvenile elephant seal carrying an electronic salmon tag detector and a time-depth recorder on its back, as well as a satellite tag on its head. Photo by Cory Champagne, UCSC

NOAA Biologist Laurie Weitkamp says the fish have presumably swum onward now to an unknown ocean hangout. 

Laurie Weitkamp: "If you want to understand how ocean conditions affect the survival of steelhead -- and this is a big question because a lot of these stocks are listed under the Endangered Species Act -- then knowing what parts of the ocean they are using is the only way you can understand why some years you get a lot back and other years you donít get very many back at all."

Tracking down the selected steelhead has got to be harder than finding a needle in a haystack.  So fellow biologist Michelle Rub says 13 elephant seals have had electronic receivers glued to their backs.  The devices detect and record if tagged steelhead pass nearby.

Michelle Rub: "The advantages of these animals are that they travel all throughout the North Pacific. They're present when the fish are actually out there."

Rub hopes to recover the tracking data on the receivers when the seals return to a rookery off northern California in December.

The research team is also using a listening array anchored on the continental shelf and a detector towed behind a ship to help find their quarry.

NW Fisheries Science Center