Green Crabs Invade West Coast: A Tribe's Fight

European green crabs, an aggressive invasive species, have become a growing problem along the West Coast, significantly threatening fisheries and aquaculture. The Swinomish Indian Tribal Community in Washington is spearheading efforts to control this burgeoning invasion before it causes irreversible damage.

The tribe's environmental scientists and researchers began trapping efforts after the first European green crab was detected in Swinomish waters late last year. So far, over a thousand traps have yielded only a dozen more of the invaders, but concern remains high due to rapid spread observed in nearby areas.

These voracious crustaceans first arrived on the East Coast in the 1800s, where they devastated local shellfish industries, causing tens of millions of dollars in annual losses. Their presence on the West Coast, first noted in San Francisco Bay in 1989, has been exacerbated by warmer waters due to climate change.

In response, Washington State declared a state of emergency in 2022. Ecologists, shellfish growers, and volunteers have since removed over 1.9 million European green crabs statewide. The focus has shifted to managing the invasion, as complete eradication has proven impossible, with the goal being to keep crab populations at biologically insignificant levels.

Efforts in various regions, including Willapa Bay, have shown the scale of the challenge, with millions of crabs removed. Researchers are also learning from past mistakes, such as an incident in California that led to population overcompensation due to improper trapping strategies. The Swinomish tribe is cautiously optimistic, emphasizing the need for continuous learning and a broader, ongoing effort to manage the persistent threat.