An invasive crab species has been spotted again in Oregon, a discovery that wildlife officials called "concerning," especially because the crab turned up this time in a different part of the state.

The Chinese mitten crab, recognized by its "hairy" claws that create a mitten-like appearance, is capable of climbing over walls as high as 13 feet and isn't native to the United States. In Oregon, the species is prohibited, to the Oregon Department of Fish and Wildlife, which has asked community members to help search for other mitten crabs that may still be in the area.

In the latest case, a Chinese mitten crab was found in the Willamette River in the Portland area. After appearing in shallow water, it was captured alive by hand, the wildlife department said in news release Tuesday. The crab was reported to the department in mid-November and was not released back into the water, it said.

The crab was found some 150 miles away from a spot along the lower Columbia River where another mitten crab was caught earlier this year. The Columbia River runs along Oregon's northern border with Washington.

"This recent confirmation is concerning for ODFW as another Chinese mitten crab was found in Oregon waters in April 2025 in a different location – marking the second confirmation of this invasive species in Oregon," the wildlife department said. "ODFW biologists are working with the U.S. Fish and Wildlife Service, Portland State's Center for Lakes and Reservoirs and the Oregon Invasive Species Council to determine if other mitten crabs are in the Willamette River."

Unlike Oregon's native crab species, which live in the ocean, bays and estuaries, mitten crabs live in freshwater and migrate to brackish water to breed, the department said. The invasive crab species originated in East Asia and first established an invasive population in the San Francisco Bay area in the 1980s, according to the . In more recent years, mitten crabs have spread to the U.S. East Coast, with one sighting last year in New York.

Along with the claws that became their namesake, mitten crabs are known for their brownish-orange or greenish-brown appearance as well as their four spines — yet another distinguishing trait that sets them apart from any native U.S. crab species. According to the , mitten crabs are capable of climbing vertical concrete walls up to 13 feet tall. In at least one instance, the crabs were able to escape from a concrete holding tank with sides that were even taller — 18 feet high.

It is illegal to possess or sell mitten crabs in Oregon, but wildlife officials said there are risks of mitten crabs entering the state through illegal food imports. Hoping to identify crabs still lurking in Oregon's rivers, officials said they are setting up artificial habitats to attract any that may still be alive and collecting water samples to look for signs of them. Additional monitoring programs are underway in the Columbia and Willamette rivers, they said.

Editor's note: This story has been updated to correct a reference to the location; the crab was found in the Portland area.