17 European green crabs trapped in Drayton Harbor, raising fears about these invaders

Seventeen European green crabs were trapped in Drayton Harbor over two days in late September, worrying those working to keep the hungry invaders from taking root here and elsewhere in Washington state.

“This is the highest number of green crabs trapped in such a short period of time from any one area along Washington’s inland shoreline,” the state Department of Fish and Wildlife said in a statement on Tuesday, Oct. 8.

What could that mean?

“Finding this many invasive green crabs so quickly in one area raises a serious concern that there may be an established and reproducing population in Drayton Harbor,” Allen Pleus, the aquatic invasive species manager for Fish and Wildlife, said in the statement.

Drayton Harbor is in Blaine.

Pleus said the state agency will work with partner Washington Sea Grant to continue trapping in the area and with local governments, tribes and other partners on a response.

The traps were set after Fish and Wildlife and the Washington Sea Grant Crab Team found evidence of European green crabs in Drayton Harbor during regular monitoring, including a shell in August.

Tribes and volunteers also are part of the effort to keep the non-native pests from making a home here and elsewhere in the state’s saltwater shorelines.

Hungry predators

Considered one of the world’s worst invasive species, Carcinus maenas are voracious eaters and skilled predators that could prey on native shore crab species, compete with native fish for food and hurt the shellfish industry here, according to Washington Sea Grant.

Native Dungeness crabs, which are smaller when they’re younger, also could be affected. There’s a commercial fishery for Dungeness in the state.

They also could destroy vitally important eelgrass beds and estuarine marsh habitats and hurt salmon recovery, officials said.

European green crabs like a variety of coastal habitats and can thrive in wide ranges of temperature and salinity, especially muddy habitats such as salt marshes with deeply cut channels and sloughing banks, according to Washington Sea Grant.

They are native to the shores of the Baltic Sea and the northeastern Atlantic Ocean, ranging from northern Africa to Norway and Iceland. They’ve been a problem on the East Coast, where they are multiplying and have been blamed for the collapse of the soft-shell clam industry in parts of Maine.

The best way to keep their numbers from growing is to trap them and to do so early.

“Managing aquatic invasive species like the European green crab is similar to preventing wildfires,” Emily Grason, a marine ecologist and Crab Team program manager at Washington Sea Grant, said in a statement.

“We keep a sharp lookout and respond quickly to small populations before they get too big to control,” Grason added.

Before the trapping that was done in late September, a total of five European green crabs had been found in Whatcom County.

Their presence in Whatcom County was first confirmed in May, when the remains of one were found in Bellingham’s Squalicum Harbor.

To help keep them from becoming established here, Fish and Wildlife is encouraging the public to keep an eye out for European green crabs when visiting the beach.

Check out “Identifying European Green Crab” on the Crab Team website (https://wsg.washington.edu/greencrab) for more on how to recognize this species.

Think you found one?

Report possible European green crab sightings by emailing crabteam@uw.edu.

Attach photos, taken from different angles and distances, of the crab to the email. Include the location. You will be contacted if more information is needed.

Leave the crab in place.

Kie Relyea has been a reporter at The Bellingham Herald since 1997 and currently writes about social services and recreation in Whatcom County. She started her career in 1991 as a reporter and editor in Northern California.