The Oregon Department of Fish and Wildlife (ODFW) has confirmed a second sighting of Chinese mitten crab – an invasive species prohibited in the state – in 2025, leading to growing concern from state biologists and officials.
According to the National Invasive Species Information Center, Chinese mitten crabs can interfere with “fish salvage operations, fish passage facilities, water treatment plants, power plants, and other facilities.”
Though the arrival of Chinese mitten crabs in San Francisco Bay caused significant damage to infrastructure in the 1990s, the species had never been seen in the Pacific Northwest prior to this year.
That all changed when a commercial fisher caught a specimen and reported it to ODFW in April 2025.
Now, a second specimen has been spotted. On 17 November, an individual spotted a live Chinese mitten crab in shallow water, captured it by hand, and alerted ODFW. The crab was not returned to the water. State biologists are now collaborating with the U.S. Fish and Wildlife Service, Portland State's Center for Lakes and Reservoirs, and the Oregon Invasive Species Council to locate any other mitten crabs nearby. Researchers are conducting shoreline walks to search for signs of the crabs, collecting samples for e-DNA testing, and setting up artificial habitats to lure any crabs out of hiding.
The state government is urging people who believe they have seen Chinese mitten crabs to share that information with ODFW.
“If you spot a crab with hairy, mitten-like claws, a notch between the eyes, or four spines on each side of the shell, take a photo, note the location, and report it to Oregon Department of Fish and Wildlife,” the department state in a social media post.
