Ringed crayfish infestation found in Willamette Watershed

The Oregon Department of Fish and Wildlife (ODFW) confirmed last week that ringed crayfish have been discovered in the Willamette River drainage, a worrying sign considering the invasive species was previously confined to Lane County’s Row River in southern Oregon.

The crayfish were discovered in Row River in September by a U.S. Forest Service (USFS) employee on a recreational dive at Wildwood Falls Park. A presence/absence survey conducted by ODFW biologists, the USFS, the Coast Fork Watershed Council and student volunteers indicated that the ringed crayfish were not present in Row River below Dorena Dam or in its tributaries Mosby, Brice and Sharps creeks.

“To find ringed crayfish in the upper end of the Willamette Basin is very alarming to us,” South Willamette Watershed District Fish Biologist Jeff Ziller said. “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.”

ODFW Invasive Species Coordinator Rick Boatner speculates that the crayfish were introduced into the watershed when used as live bait. Anglers are barred by law from using non-native crayfish as bait unless they were taken from the same waterbody, and it is illegal to release non-native crayfish.