Wildlife officials are sounding the alarm after an invasive and potentially damaging crab species was found in the U.S. for the second time this year.
According to the Oregon Department of Fish & Wildlife, the Chinese mitten crab, was found in the Willamette River near the Sellwood Bridge on Nov. 17. The discovery follows a crab being found in a different location in April.
The crab was caught by hand and removed from the river. ODFW called the discoveries “concerning” in a news release earlier this month.
Chinese mitten crabs are known to burrow into dikes, levees or stream banks which can increase erosion and damage flood control and water supply systems.
Additionally, the 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.
Mitten crabs live in freshwater and migrate to brackish water to breed, unlike Oregon’s native crab species that live in the ocean, bays, and estuaries.
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.
It is unlawful to possess and sell mitten crabs in Oregon, but there is a risk of them being illegally imported and sold in the food trade and then released alive into Oregon waters.