SCOTT DETROW, HOST:
An invasive crab species has found its way to the self-styled oyster capital of the world. That's Willapa Bay on the coast of southwest Washington state. Shellfish growers are - on the bay are alarmed. They want aggressive action. Tom Banse of the Northwest News Network reports.
WARREN COWELL: OK, there we have some green crab, right off the bat.
TOM BANSE, BYLINE: Warren Cowell owns Willapa Bay Shellfish. He and other oyster and clam growers are hunting down invasive European green crabs.
COWELL: Fourteen, 16.
BANSE: On the state's dime, Cowell's crew hauls up and empties dozens of traps placed around the commercial clam and oyster beds offshore of Nahcotta, Wash. The square mesh traps come up filled, mostly with juvenile native Dungeness crabs. But sprinkled in are darker colored, slightly differently shaped green crabs. Crew member Niko Hora sorts by hand and tosses the native Dungeness back, all the while trying not to get pinched.
NIKO HORA: I have to be careful with it especially with the Dungeness. The green crab - they don't pinch you that hard, but Dungeness will.
BANSE: The crew collected 109 green crabs in less than two hours.
HORA: And that's it.
COWELL: With over a year of trapping, our numbers still are very high.
BANSE: Encouragingly, though, Cowell says it's down from a peak seen last fall. The undesirable European green crabs will be frozen to death and then sent to a landfill. The proliferation of these invasive shore crabs is causing alarm from Maine all the way around to Alaska. Cowell says the stakes are especially high at this shallow, sheltered saltwater bay.
COWELL: They'll eat all the shellfish if they get established and move on to everything else that they can eat. All the habitat - the eelgrass, which is so important, and they even take that out eventually.
BANSE: According to the Pacific Shellfish Institute, Washington state is by far the largest producer of Manila clams in the U.S. and a leading producer of oysters. More than two-thirds, at least $15 million a year worth, of the state's oysters come from Willapa Bay.
(SOUNDBITE OF WATER SPLASHING)
BANSE: State biologists and the local growers say crab trapping is presently the only way to control the invaders that threaten that bounty. Cowell is calling for a trapping blitz this year.
COWELL: We're at the tipping point if we haven't passed it. And so we have to trap and trap as aggressively as we possibly can, at least to hold the line until we can come up with better solutions.
BANSE: Which is along the lines of how the state Fish and Wildlife Department is thinking about this. Allen Pleus is the state's aquatic invasive species manager. He says his agency has spare traps and is hiring more seasonal help this year to protect high-value sites.
ALLEN PLEUS: This is a problem that's going to persist for a long time, and we're looking at long-term solutions. What are the genetic possibilities for creating, you know, like, sterile males or, you know, some other method that we could use?
BANSE: Pleus says localized control seems possible, but eradication at the statewide level is not a realistic goal because ocean currents are constantly resupplying green crab larvae from afar.
PLEUS: They get repopulated by larvae coming from the south and coming from the north, and there's just no bottleneck for that larvae.
BANSE: The invaders are edible, but have little meat in their shells and don't grow as large as Dungeness crabs or command a high price, like blue crab. Oregon and some New England states welcome recreational crabbers to knock back the green crabs, but so far, sport fishers are showing minimal interest.
For NPR News, I'm Tom Banse in Nahcotta, Wash. Transcript provided by NPR, Copyright NPR.