SEDRO WOOLLEY– An updated version of a device that has been used for at least 200 years to catch fish is being put to work on the Skagit River for a new purpose– to give scientists more information on the number of threatened chinook salmon that return upstream to spawn.
The Washington Department of Fish and Wildlife (WDFW), and a local volunteer organization, the Skagit Fisheries Enhancement Group (SFEG), sought grant funding for a fish wheel as a way to get more information on the numbers of returning salmon.
The pilot fish wheel was fabricated by a consultant, LGL Ltd. of Sidney, B.C., under a $136,000 grant from the U.S. Chinook Technical Committee to WDFW and the Skagit RFEG.
Fish wheels have been used to harvest fish for two centuries. They were banned decades ago for commercial fishing in this state and Oregon because of the high numbers of fish they caught.
But now with efforts focused on monitoring and recovering Puget Sound chinook and other wild salmon, fish wheels are gaining popularity as a way of collecting live adult fish for monitoring studies without harming them.
The Skagit River is the largest tributary of Puget Sound and home to thousands of Puget Sound chinook, which are under federal protection as a threatened species.
"We need some way to capture and mark adult fish with little or no mortality," said WDFW Director Jeff Koenings. "Fish wheels have worked well for this purpose in large rivers in Canada and Alaska."
The new fish wheel, mounted on floating aluminum pontoons, consists of net baskets at the ends of rotating metal struts which turn like a Ferris wheel with the river current. The baskets face downstream and scoop up fish as they migrate upriver to spawn and complete their life cycle.
Fish collected in the baskets are deposited into a tank of water where technicians note the species, size and sex of each fish and mark it with a small tag the width of a strand of spaghetti before releasing it back into the river.
Scientists later will survey the marked fish after they have spawned upstream, completed their life cycle and died. That information will indicate where the marked fish went and how many survived to spawn, as well as helping in assessing the accuracy of data collected by other monitoring methods.
Because the wheel collects all species of passing fish, it also can be used to monitor the strength of other fish runs besides chinook. The returning chinook run is expected to peak in early August in the section of the river where the fish wheel is located.
While the fish wheel operation is being tested in the river, it will be located at a boat access site on the north side of the river near the Sedro Woolley Wildcat Steelhead Club, 24910 River Road.