European green crabs, an invasive species long established on the U.S. East Coast, are increasingly threatening marine ecosystems and fisheries along the West Coast, prompting urgent efforts to control their spread. Native to Europe, these aggressive crabs first arrived on the East Coast in the 1800s, where they have since caused significant damage by disrupting eelgrass beds and preying on native shellfish such as clams, mussels, and juvenile lobsters. Now, similar concerns are mounting in Washington state, particularly among Native American tribes whose livelihoods and cultural practices depend heavily on fishing and aquaculture.
The Swinomish Indian Tribal Community, based in Puget Sound, has taken early action following the discovery of the first European green crab in their waters late last year. Environmental scientist Sarah Grossman, working with the tribe, described initial alarm upon the first capture. Since then, approximately 1,000 traps have been deployed, yielding only a handful of crabs, but officials remain vigilant given the rapid population surges observed by nearby tribes like the Lummi.
Joe Williams, a Swinomish fisherman involved in restoring traditional clam gardens, emphasized the vulnerability of their shellfish resources. Native clam populations have already declined due to environmental degradation, and the introduction of green crabs represents an additional and serious threat. The Lummi Tribe’s experience, where occasional sightings escalated to tens of thousands in a few years, serves as a cautionary example.
The crabs were first recorded on the West Coast in 1989, likely transported as larvae on ships, and have since expanded their range from San Francisco Bay northward to Vancouver Island and Alaska. Warmer waters driven by climate change are believed to facilitate their proliferation. In response, Washington state declared a state of emergency in 2022. Since then, more than 1.9 million crabs have been removed statewide through coordinated trapping efforts involving ecologists, tribal communities, and volunteers.
Despite these efforts, experts acknowledge that eradication is unlikely. Lindsey Parker, a biologist leading Washington’s green crab response, noted that due to established populations to the north and south, ongoing management will be necessary. Todd Gray, an ecologist with the Tulalip Tribes, highlighted the importance of early detection and rapid response to keep populations low.
Willapa Bay in southwestern Washington represents the worst-affected area, with the majority of captured crabs coming from its shallow waters. Marine ecologist Emily Grason, who leads monitoring efforts there, reported an increase in crab numbers compared to previous years, indicating that the population may be growing despite intensive trapping.
Other jurisdictions, including Alaska, California, and British Columbia, are also engaged in trapping programs. Tribal groups such as Alaska’s Metlakatla community remove tens of thousands of crabs annually. Natural predators like sea otters can assist, but the overall challenge remains formidable.
Studies caution, however, that overly aggressive trapping can backfire due to the crabs’ cannibalistic behavior. In California, removing mostly adult crabs inadvertently led to a population surge among juveniles, a phenomenon known as overcompensation. This underscores that total eradication is improbable, and that the primary management goal is to maintain the crabs at biologically inconsequential levels.
Swinomish Chairman Steve Edwards expressed cautious optimism about ongoing efforts, emphasizing the need for a larger-scale response. Meanwhile, local fishers like Williams recognize that containment is a long-term endeavor, acknowledging that coastal communities may ultimately have to adapt to the presence of this persistent invasive species.