Invasive Chinese Mitten Crab Discovered in Pacific Northwest

A fisherman in the Pacific Northwest recently caught an unexpected species—the Chinese mitten crab, marking the first time it has been found in the region. This invasive crab, native to eastern Asia, poses a serious threat to local ecosystems and the fishing industry.

What Is the Chinese Mitten Crab?
Recognizable by its hairy, mitten-like claws, this crab thrives in both saltwater and freshwater. Its ability to adapt, coupled with its appetite for plants and animals, allows it to outcompete native species and damage habitats. It can grow up to four inches wide and is known to burrow, causing harm to riverbanks and infrastructure.

The Discovery and Concerns
The crab was caught on April 22 near Astoria, Oregon, in the Columbia River. Experts suspect it may have arrived via ship ballast water or was illegally released. Its appearance has raised alarms among scientists and prompted collaboration between Oregon, Washington, and NOAA to assess the situation.

Next Steps
Officials are deploying traps and analyzing water and sediment to detect more crabs. The public is urged to report any sightings immediately to help prevent a wider invasion.

A History of Harm
This isn’t the first U.S. sighting. The mitten crab was first found in San Francisco Bay in the 1980s, where it caused significant ecological and infrastructure damage. The current discovery raises fears it could spread north and repeat this destruction.

Hard to Contain
Mitten crabs are hard to control due to their durability—they can survive over a month in moist conditions and even climb past barriers.