Invasive European green crabs have most likely found permanent habitat in coastal waters off Washington state and parts of Puget Sound.

The question is whether the state can curb the aquatic pests enough to prevent serious harm to native wildlife, coastal ecosystems and the commercial shellfish industry. The Washington State Department of Fish and Wildlife, tribes, shellfish farmers and local conservation districts are all taking part in the fight against unwanted shellfish.

“It’s one of the few environmental issues where everyone has basically the same goal of reducing the number of green crabs in Washington state,” said Emily Grason, crab team manager for Washington Sea Grant. “It’s brought together a lot of groups that don’t always work together.”

Capture is the main method of control. As of Aug. 4, the Department of Fish and Wildlife said about 905,320 European green crabs had been caught since 2022 — more than 258,888 this year.

“We are seeing signs of effective green crab control and progress in limiting its spread in the Salish Sea portion of Washington state, but this invasive species remains abundant in coastal bays, particularly Willapa Bay and Grays Harbor Bay,” agency spokesman Chase Gunnell said in an email.

“Intensive fishing will continue to be necessary in these areas to prevent impacts on clam and oyster farmers, native molluscs and estuarine habitats,” he added.

Last year, Parliament approved about $12 million in the current two-year budget to manage the European green crab population.

The Department of Fish and Wildlife is on track to send a six-year green crab response plan to the Legislature and governor by Oct. 1. In it, the department is preparing to recommend $12 million in additional state funding over the two-year budget cycle. The agency also plans to push for federal funding.

Fish and Wildlife reported in mid-August that the crabs were first detected in the Quillayute River estuary near La Push. Chelsey Buffington, who leads the agency’s efforts to deal with the crabs, described the discovery as not surprising, given the populations to the north in Makah Bay and to the south around Grays Harbor and Willapa Bay.

The Quileute Tribe has been setting out crab traps around the Quillayute River since 2021 but has failed to catch a single green crab.

“Now that we know they’re here in the Quillayute River system, our management strategy will have to be reconsidered,” said Jennifer Hagen, a marine policy advisor and marine biologist for Quileute Natural Resources. “Ultimately, our concern is the displacement of native species and species that are culturally significant to the Quileute Tribe.”

“It requires a break from nature”

European green crabs began spreading along the country’s eastern seaboard in the 1800s, arriving by ship. They were first found in the late 1980s on the western seaboard and began appearing in Washington waters about five years ago.

Sea Grant’s Grason 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 the timing of this invasion,” she said.

There are also features of the state’s coastline that provide advantages in the fight against crabs.

Still, Grason noted that the past winter was warm, which has helped green crabs spread and survive. “People who fish in coastal estuaries are seeing catch rates that are at least two to three times higher than they were this time last year,” she said.

Cold winter weather—even a freezing snap—can kill crab larvae. Something that helps keep larvae out of Puget Sound and the broader Salish Sea is that rivers in Washington and British Columbia, including the Fraser, push water near the sea surface from the Strait of Juan de Fuca into the Pacific. Larvae coming from the coast, swamped by that topwater, are blocked by the westward current. But winter storms can sometimes cause the current to reverse, sweeping larvae east into the Salish Sea.

“Trying to control the green crab population requires not only hard work on the part of humans, but also a break from nature,” Grason said.

There is evidence to suggest that green crab populations can be suppressed in specific locations. But Grason added: “We don’t believe we can completely eradicate them” from Washington waters. “We’re trying to figure out what the best solutions are to get a realistic outcome,” she said.

David Beugli, director of the Willapa-Grays Harbor Oyster Growers Association, said the seven shellfish farms that are part of the group are catching green crabs this month and that the number of farmers catching them will be slightly higher in the coming weeks. Shellfish farmers have played a key role in controlling the crabs, catching thousands of them. It’s work that takes place mostly this time of year and in the fall. In the winter, the water is too rough to check the traps often.

Beugli said there have been isolated reports of damage to oysters and clams in his region, but so far there has been no major damage.

The crab hunt means extra work for companies that may already be struggling to find workers. But the consequences of their spread could be serious for the industry, as the invaders prey on, and may even harm, the species that shellfish farmers harvest.

A green crab can eat 40 half-inch clams a day and may feed on other crabs its own size or young oysters. As it digs for food, it can damage seagrass, estuaries and marshes. Dungeness crabs, native fish and some birds may also be threatened by the invasive crabs.

Green crabs, although edible, are about the size of a fist and not very appealing culinary-wise. They are often added to soups and broths when used for cooking.

Beugli appreciated the state’s efforts. But he also said some shellfish farmers are frustrated and would like to see more support, perhaps a massive trapping effort in Willapa Bay. “I just don’t know how we can do it,” he said. “It’s kind of a specialized skill to get out there and understand the bay and where to trap. And the farmers know that better than anyone.”

As for how big a threat the crabs might pose to the industry, he said there are still many unknowns. “We’re keeping the numbers at a level where we don’t harm the environment,” he said. “I don’t know what the tipping point will be.”