Hairy, Invasive, Wall-Scaling Crabs are Appearing in Oregon and Officials are Concerned

Oregon Wildlife Officials on Alert After Second Invasive ‘Hairy’ Crab Discovery

Oregon’s wildlife officials have raised concerns following the detection of yet another invasive species – the “hairy” Chinese mitten crab. This sighting is the second of its kind in the state this year and is causing worry among biologists about the potential threat these crabs pose to local wildlife.

The Chinese mitten crab is easily recognisable by its furry, mitten-like claws, four side spines, and a notch between the eyes. The Oregon Department of Fish & Wildlife confirmed that a medium-sized crab with distinct features was found in the Willamette River near Portland, Oregon. These crabs are not indigenous to the United States and typically measure around 3 inches wide, appearing in shades ranging from brownish-orange to greenish-brown.

According to reports, the latest sighting took place in the shallow waters of the Willamette River on Monday, November 17. Wildlife officials removed the crab from the river without harm, as these invasive crustaceans have the incredible ability to scale walls up to 13 feet high. This sighting marks the second confirmed encounter with the Chinese mitten crab in 2025, with a previous sighting in April in a different location in Oregon.

Experts at the Oregon Department of Fish & Wildlife are working diligently to assess whether these invasive crabs are establishing a local population in Oregon’s waterways. Biologists are collaborating with various organisations to conduct thorough searches for additional mitten crabs in the Willamette River. Their methods include setting up artificial habitats to attract these crabs, testing water and sediment samples for environmental DNA, and visually inspecting shorelines for any molted shells.

The presence of Chinese mitten crabs in Oregon poses a significant risk to the state’s natural ecosystems. These crabs are known to burrow into levees, dikes, and stream banks, leading to increased erosion and a threat to flood-control systems. Additionally, they prey on native species, consume fish eggs, and compete with local fish and crayfish for food, creating a disruption in the ecological balance.

The Oregon Department of Fish & Wildlife is urging the public to report any potential sightings of Chinese mitten crabs to help monitor and control their spread. Given their resemblance to Oregon’s native hairy shore crab, it is crucial to differentiate between the two species accurately. The agency has provided an online platform for reporting sightings and encourages the public to submit photographs for identification purposes.

In conclusion, the discovery of the invasive Chinese mitten crab in Oregon has prompted wildlife officials to step up monitoring efforts and raise awareness among the public. The threat these crabs pose to the local ecosystem underscores the importance of early detection and swift action to prevent their establishment and proliferation in Oregon’s waterways. Vigilance and cooperation from the community are essential in safeguarding the state’s biodiversity and natural habitats from the harmful effects of invasive species.