Illegal Food Trade Fears Grow in Oregon After Invasive Chinese Mitten Crabs Turn Up in the Willamette River
On two occasions in 2025, a Chinese mitten crab, a prohibited species in Oregon, was found in the Willamette River near the Sellwood Bridge. The Oregon Department of Fish & Wildlife (ODFW) is seeking help identifying the origin of the crabs.
Source: ODFW 2025 mitten crab releases and Smithsonian Invasion History
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Non-Native Chinese Mitten Crabs Found In The Willamette River
A Chinese mitten crab was found in Oregon waters in April 2025 at a different location, and on November 17, a second member of this invasive species was found in the Willamette River. It was spotted in shallow water, captured alive by hand, and not released back into the river.
Unlike Oregon’s native crab species, which live in the ocean, bays, and estuaries, the Chinese Mitten crab is a non-native species that spends its adult life in freshwater and migrates to brackish water to breed.
It is unlawful to possess or sell mitten crabs in Oregon. The U.S. Fish and Wildlife Service, Portland State’s Center for Lakes and Reservoirs, and the Oregon Invasive Species Council joined forces with ODFW biologists to determine if other mitten crabs are in the Willamette River.
These medium-sized crabs, about 3 inches wide, prey on native species, consume fish eggs, and compete for food, potentially impacting native fish and crayfish populations. ODFW warned that Chinese mitten crabs burrow into dikes, levees, and stream banks, worsening erosion and threatening flood-control systems.
Mitten crabs, named for their hairy mitten-like features located on the outside of their claws, vary in color from brownish orange to greenish brown and have a notch between their eyes and four spines on each side of the carapace. ODFW published a Visual identification guide for crabs in Oregon.
| Feature | Chinese mitten crab | Common Oregon natives |
|---|---|---|
| Claws | Hairy "mittens" | Not densely hairy |
| Habitat | Adults in freshwater | Most live in ocean, bays, estuaries |
| Carapace edges | Four spines per side | Different spine patterns |
| Between eyes | Distinct notch | Varies by species |
ODFW warned that there is a risk of mitten crabs being released alive into Oregon waters after being illegally imported and sold in the food trade.
With the opening of native Dungeness crab season later this month, wildlife officials are concerned about potential infestations of this non-native, highly invasive crab species.
Source: Oregon Sea Grant 2024 commercial landings summary
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The agency has asked the public to report any suspected unlawful sales and to submit photographs to the hotline to help confirm crab identification, as native crabs have previously been misidentified as invasive.
ODFW stressed the importance of correctly identifying Chinese mitten crabs and reporting sightings to 1-866-INVADER or online via the Oregon Invasive Species reporting hotline form.