A banned Chinese mitten crab was found alive in Oregon’s Willamette River, raising concerns about ecosystem damage and spread.

A Chinese mitten crab, an invasive species banned in Oregon, was found alive in the Willamette River near the Sellwood Bridge, marking the second confirmed sighting this year. State biologists are investigating potential spread using traps, water sampling, and surveys, as the crabs can damage infrastructure, disrupt ecosystems, and threaten native species. Unlike native crabs, they live in freshwater and migrate to brackish water to breed. Officials warn the crabs may enter illegally through the food trade and urge the public to report sightings or sales via the Oregon Invasive Species hotline.