Crabbing season in WA: Not all invasive European green crabs are green

SEATTLE - Crab season is in full swing around western Washington, and this summer, scientists have detected new sightings of invasive European green crab along Hood Canal.

Chase Gunnell, communications manager at the Washington Department of Fish and Wildlife, joined Good Day Seattle on Wednesday to talk more about the invasive species and what makes them such a menace to local ecosystems.

What is the European green crab?

"The European green crab is an invasive species. They're native to Western Europe, like the name says. They've been here in the Pacific Northwest for a little over 20 years now. But with this warmer weather we've been seeing the last few years, these warmer summers, we've seen a real growth in this invasive crab, and it's a concern for our ecosystem and some of our native species," said Gunnell.

How do European green crabs harm WA's local ecosystems?

"We're really worried about the impact these crabs could have on our native shellfish like Dungeness – also clams and oysters," said Gunnell. "They can eat up to 40 small clams a day, and we love our clams. We want to eat them."

"They can also have a big impact on eelgrass, which is an important piece of the marine environment for everything from forage fish, to salmon, to southern resident orca whales that eat those salmon."

The Washington State Legislature has given the Department of Fish and Wildlife, a number of Native American tribes and other partners like University of Washington resources to trap and monitor these invasive crabs.

"So all the work that we've put into restoring Puget Sound and our local ecosystems, this is an invasive species that could literally undermine that work. So it's really important that we get out and try to trap their numbers down to a level where they're not having an impact."

Can you eat European green crab?

Yes. European green crabs are edible and can be prepared in various ways. They're sometimes eaten in their native European range, and there is growing culinary interest in areas where they are invasive, such as the New England area. However, officials in Washington are asking the public not to hunt them recreationally.

"My colleagues on the East Coast would say that they're a lot of shell, not very much meat, and nowhere near as delicious as some of our other crab species," said Gunnell. 

In East Coast cuisine, green crabs are used primarily for their roe and in stocks.

In Washington, many people familiar with the invasive species often ask: If green crabs are harmful to the environment, why not just eat them until they’re gone? Local wildlife officials say the key issue is misidentification.

"Here in Washington, we're not encouraging the public to go out and catch and cook them, just because issues have arose with misidentification of some of our native crabs," said Gunnell. 

Green crabs are small and can be mistaken for native species, such as juvenile Dungeness.

How to identify an invasive European green crab

European green crabs are not always green

"Color is not always a good way to identify the European green crab," said Gunnell. "They can be orange, they can be yellow, they can be brown."

European green crabs are small and live closer to shore

"What really surprises people is how small these crabs are. These are actually what's called shore crabs, so they live right along the shore in the shallow intertidal water. They're not usually out in that deeper water where we might go crab for Dungeness, and they don't get very big. They're no bigger than about four inches across," said Gunnell.

European green crabs have five distinct spines on their shells

"The way we ask folks to identify them is these five spines on either side of their shell. None of our native crab species have five spines, and when you look at the green crab, there's some pretty distinct spines there that help identify them."

What are the chances invasive green crabs will spread into Puget Sound?

"Yeah, so there is a risk. We've been seeing some new detections this summer in northern Hood Canal, in the Port Gamble area, as well as over by Port Ludlow," said Gunnell.

"We're grateful that our teams, as well as our partners, are out there trapping so we can get on those detections early, and then we can really follow up with heavy trapping to try to stop their spread south into Puget Sound."

"Unfortunately, at this point, we don't expect to be able to eradicate this invasive species. There's just too many of them out on the coast and down in Oregon and California, but we think we can minimize the risk by keeping their numbers at a really low level – where they're not hurting either our local economy like shellfish growers, the environment and the recreational activities that we prize like going out catching crab, Dungeness crabs."

For more information on the invasive European green crab, visit the Washington State Department of Fish and Wildlife's website.

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