The U.S. environmental authorities in Oregon have raised alarms after confirming the first documented presence of an invasive species—the Chinese mitten crab (Eriocheir sinensis)—in the Columbia River near the Oregon-Washington border. The discovery, announced by the Oregon Department of Fish and Wildlife (ODFW), marks a significant ecological concern for the region.
A commercial fishing crew reportedly hauled in the crab—a large adult male—during routine operations last week in the Lower Columbia River. Officials emphasized that while this is the first confirmed case in the Pacific Northwest, the species has a troubling history elsewhere. In the 1990s, rapid proliferation of these crabs severely disrupted ecosystems and infrastructure in California's San Francisco Bay.
"The origin of this specimen remains unclear," authorities noted in a statement. "It may have been illegally introduced by humans or transported inadvertently as larvae in ship ballast water." The ODFW has urged residents, anglers, and researchers to immediately report any sightings, providing detailed photographs and precise locations to aid tracking efforts.
Profile of the Chinese Mitten Crab
Native to coastal regions of East Asia, the Chinese mitten crab is classified as a highly invasive species due to its adaptability and destructive habits. Recognizable by distinctive patches of hair resembling "mittens" on its claws, the crab also features a notch between its eyes and four lateral spines on its shell. Coloration ranges from rusty orange to muted green-brown.
Notably, the species has demonstrated remarkable resilience, capable of migrating long distances and scaling barriers over 4 meters (13 feet) high. Beyond ecological damage, their burrowing behavior has been linked to erosion of riverbanks and damage to irrigation systems.
Prior U.S. encounters include established populations in San Francisco Bay and isolated sightings in Chesapeake Bay (2005) and Mid-Atlantic waterways (2005–2014). In Europe, the crab has infiltrated rivers from Germany to the UK, prompting costly containment measures.
Global Implications and Local Response
The Columbia River discovery underscores the ongoing challenge of invasive species in an era of global shipping and climate shifts. While the long-term impact remains uncertain, experts warn that unchecked spread could threaten native salmon populations, compete with local fisheries, and strain flood-control infrastructure.
"Early detection is critical," the ODFW emphasized. "Public cooperation can help prevent a repeat of past ecological crises."