“To find Ringed crayfish in the upper end of the Willamette Basin is very alarming to us,” said Jeff Ziller, South Willamette Watershed District Fish Biologist. “Ringed crayfish have been found to outcompete our native Signal crayfish for habitat and food. The non-native ringed crayfish dominate the crayfish populations in the Rogue, Chetco and Umpqua rivers, so this is bad news for Signal crayfish here in the Willamette system.
While on a recreational dive in late September, a U.S. Forest Service employee discovered two Ringed crayfish below the falls at Wildwood Falls Park on the Row River. With assistance from the USFS, the Coast Fork Watershed Council, and student volunteers, ODFW biologists conducted a presence/absence survey by placing numerous crayfish traps below and above the initial discovery site and some tributaries of the Row River down into Dorena Reservoir.
Adult Ringed crayfish were found below the falls between the park and reservoir. Only native Signal crayfish were found in the Row River below Dorena Dam and in sampled tributaries including Mosby, Brice and Sharps creeks.
Rick Boatner’s experience with these invasive crayfish tells him they were possibly used by anglers as bait or were illegally released into the wild by someone who had them as a pet. Boatner is ODFW’s invasive species coordinator and said it’s illegal to use live, non-native crayfish as bait except in the waterbody in which they were taken. It is also illegal to release non-native crayfish into the wild.
Boatner asks people to report any findings of Ringed crayfish or other non-native crayfish to ODFW and to not return them to the waterway. To report sightings of invasive species, call 1-866-INVADER or report it online at http://oregoninvasiveshotline.org or call ODFW at 503-947-6308.
Native Signal crayfish have smooth claws with a white “signal” spot on claw pivot and a wide body plate on the back. Learn more about crayfish here.