Invasive Green Crabs Are Causing a Major Environmental Threat From Coast to Coast

by Craig Garrett
Defensive crab after being caught - stock photo

One of the most widely distributed invasive marine species on Earth is the European green crab. They can crowd out other native shellfish. Emily Grayson is a marine ecologist and the program lead of Washington Sea Grant’s Crab Team. The team has been working to contain invasive crab species since 2015.

Grayson only needs to see a few green crabs before she dons her fishing equipment and uses large traps to catch them out of the water. However, filling traps is just the tip of the iceberg. If they’re that abundant, “we’ve already missed a really important chance to actually effectively intervene in the invasion”, she told Accuweather.

Green crabs and other invasive species that prey on clams, oysters, and lobsters have been Grayson’s top concerns. And the Pacific Northwest will be less susceptible to more of them due in part to her efforts. The state of Washington has issued an emergency order to address the surge in a record 176,000 Green crabs that have been destroyed so far this year, threatening economic prosperity.

They’ve recently been making headlines from Maine to New York. Climate change is considered to be the cause behind the increase from coast to coast, according to scientists. Green crabs prefer warmer temperatures and ocean temperatures are rising. According to researchers, warmer seas may aid green crab’s earliest life phases’ survival and allow them to survive further north. They’ve just expanded their range into Alaska in recent years.

Taking proactive measures to control the spread of green crabs may assist leaders in planning long-term solutions, according to Grayson. “We’re realistic we may never totally get rid of the species. But being able to buy ourselves time is really valuable,” she explained.

The growing threat of green crabs

In only two years, the green crab population in Puget Sound and Washington’s coast exploded from 1,800 to 102,000. In response to this significant threat, a series of disaster declarations were made by the Lummi Nation and Makah Tribe concerning the cultural and economic impacts of these crabs. Washington State Governor Jay Inslee followed their lead and issued an emergency order to mobilize state resources.

Many partners, including the Washington Department of Fish and Wildlife, Lummi Nation, Makah Tribe, Shoalwater Bay Tribe, Stillaguamish Tribe of Indians, Washington Sea Grant, National Oceanic and Atmospheric Administration, Environmental Protection Agency, Bureau of Indian Affairs, U.S. Fish and Wildlife Service, and U.S. Geological Survey have been working together to establish a green crab monitoring network along the Pacific Coast and Puget Sound to help protect against invasive European green crabs.

The coordinated program has done well in finding and getting rid of small populations of the foreign crab. However, large groupings with 86,000 green crabs were recently discovered at Lummi Sea Ponds. This proves how susceptible Puget Sound and Washington’s coast are to a full-blown infestation.