ODFW employee shows a radio tag that will be inserted into a Rogue River spring chinook.

ODFW employee shows a radio tag that will be inserted into a Rogue River spring chinook.

The final product: a radio tagged hatchery spring chinook.

ROSEBURG, Ore. – To better understand migration habits of Rogue River spring chinook, ODFW biologists recently began inserting radio tags in the stomachs of these fish as they enter the river. About 30 fish will be tagged from April through early July.

This pilot research project was required by the 2007 Rogue River Spring Chinook Conservation Plan which addresses a sharp decline in returns of wild spring chinook and a change in their life history that occurred after Lost Creek Dam was built in the late 1970s. Before the dam was built, wild spring chinook returns averaged 28,000 and that average has dropped to 9,000 since 1990 despite decreased ocean harvest rates.

According to fisheries researcher Tom Satterthwaite, the pilot study will help plan a future research project designed to improve management of this important population of wild fish.

“Results from this year will tell us how to best capture and tag and fish, and most importantly, the minimum number of fish that need tagged to get statistically reliable results,” Satterthwaite said. “We need to know this number because successful upstream migration of tagged chinook in other rivers varies from 30 percent to 90 percent, and in the Rogue, these fish face added stress from high summer water temperatures.”

Biologists will use nets to capture and radio tag both hatchery and wild spring chinook at sites near Gold Beach. Anglers who find a radio tag in the stomach of any fish are asked to return the tag to a local ODFW office. 

The United States Army Corps of Engineers (USACE) is also helping with this year’s project. Signal receivers designed for tag detection have been installed in two locations by USACE scientists. These units will record the date and time when radio tagged fish migrate past the receivers. 

Results from the pilot project should be available by late autumn, and details on the future research project are outlined in the conservation plan. Copies of the plan