Invasive European green crabs have likely found a lasting home in Washington’s coastal waters and parts of Puget Sound.
The question now is whether the state can pinch down hard enough on the aquatic pests to prevent serious harm to native wildlife, shoreline ecosystems and the commercial shellfish industry. Washington’s Department of Fish and Wildlife, tribes, shellfish growers and local conservation districts are all taking part in the battle against the unwelcome crustaceans.
“This is one of the rare environmental issues that everybody has, basically, the same goal, which is to see fewer green crabs in Washington,” said Emily Grason, crab team manager at Washington Sea Grant. “It’s brought together a lot of groups that don’t always work together.”
Trapping is the main method in the fight. As of early August, the Department of Fish and Wildlife said about 905,320 European green crabs have been captured since 2022 — more than 258,888 of that total this year.
“We’re seeing signs of successful green crab population control and progress limiting their spread in Washington’s portion of the Salish Sea, but this invasive species remains prolific in coastal bays, particularly Willapa Bay and Grays Harbor,” Chase Gunnell, an agency spokesman, said in an email.
“Sustained heavy trapping will continue to be required in those areas to prevent impacts on clam and oyster growers, native shellfish and estuary habitat,” he added. Washington’s Department of Fish and Wildlife is asking the public not to kill suspected green crabs and instead report their sightings.
The invasive species is growing in numbers in Southeast Alaska too. They were discovered by members of the Metlakatla Indian Community Department of Fish and Wildlife in 2022, and since then the department has removed more than 3,000 of the green crabs, as of this past summer.
Further evidence of the crabs was discovered in June, on the shore of Gravina Island’s Bostwick Inlet, less than 10 miles southwest of downtown Ketchikan.
The Alaska Department of Fish and Game is asking the public to report any sightings.
Last year, the Washington Legislature approved about $12 million in the current two-year budget for European green crab management.
The Washington Department of Fish and Wildlife is on track to send a six-year green crab response plan to the Legislature and the governor. In it, the department is recommending continued state funding at $12 million per two-year budget cycle. The agency intends to press for federal funding as well.
Fish and Wildlife said in mid-August the crabs had, for the first time, been detected in the Quillayute River estuary near La Push. Chelsey Buffington, who leads the agency’s efforts to deal with the crab, described the discovery as unsurprising given populations to the north in Makah Bay and the south around Grays Harbor and Willapa Bay.
“Now that we know they are here in the Quillayute River system, our management strategy will need to be revisited,” said Jennifer Hagen, marine policy advisor and a marine biologist with Quileute Natural Resources. “Ultimately our concern is the displacement of native species and species that are of cultural importance to the Quileute Tribe.”
European green crabs began spreading on the nation’s eastern seaboard in the 1800s, arriving by ship. They were first found in the late 1980s on the West Coast and began to surge in Washington’s waters about five years ago.
Grason, with Sea Grant, pointed out that, unlike places in the East where the crabs have been around for a century or more, Washington is catching them at an earlier stage. “We have a unique opportunity in terms of our timing with this invasion,” she said.
There are also features of the state’s coastline that offer advantages when combating the crabs.
Still, Grason noted that this past winter was warm, which is favorable for green crabs’ spread and survival. “The folks who are trapping in the coastal estuaries are seeing catch rates at least two to three times what they were this time last year,” she said.
A cold winter — even a cold snap — can kill off crab larvae.
Something that helps keep the larvae out of Puget Sound and the Salish Sea more broadly, is that rivers in Washington and British Columbia, including the Fraser, push water near the sea’s surface out the Strait of Juan de Fuca, into the Pacific. Larvae originating on the coast, awash in this top layer of water, are blocked by the westward current. But winter storms can sometimes cause the current to reverse, sweeping the larvae eastward into the Salish Sea.
“Doing anything to try to control the population of green crab requires not only a lot of hard work from people, but it requires getting a break from nature,” Grason said.
There’s evidence showing it’s possible to suppress green crab populations at individual sites. But Grason added: “It is not the case that we believe that we can fully eradicate them” from Washington’s waters. “We’re trying to figure out what the best solutions are for a realistic outcome,” she said.
David Beugli, director of the Willapa-Grays Harbor Oyster Growers Association, said shellfish operations are catching green crabs this month. Going after the crabs means added work for businesses that can already struggle to find employees. But the consequences of letting them spread could be severe for the industry, as the invaders prey on and can otherwise harm species that shellfish growers harvest.
A green crab can eat 40 half-inch clams a day and can feed on other crabs their own size or young oysters. By digging for food, they can damage eelgrass, estuaries and marshes. Dungeness crabs, fish and some birds could also be at risk from the invasive crabs.
While edible, green crabs are only about fist-sized, not known for their culinary appeal, and are often tossed into soups and stocks if used for cooking.
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