The currents of the Salish Sea may bring invaders into Puget Sound — European green crabs hidden beneath the water, blending in with native crabs.
Volunteers are on the lookout here, and so far the search for the invasive crabs has proven fruitless, which is welcome news to wildlife managers and the state’s multimillion-dollar shellfish industry.
Peter Heffelfinger leads a four-person Salish Sea Stewards volunteer team that takes a post at a lagoon adjacent to the Kukutali Preserve on Kiket Island near Anacortes.
The group convened Saturday to document crabs and fish stuck in traps they had set the night before.
Dozens of small crabs — mostly native hairy shore and purple shore varieties — were clamoring to get out of the cages as they were pulled from the water.
The abundance of native crabs and a handful of staghorn sculpin fish was good news.
Heffelfinger said he and his team hope to see no sign of green crabs for the remainder of the season.
“They’re not here yet, but with the warming of the ocean ... they have reached Vancouver Island,” Heffelfinger said. “It’s only a matter of time and tide.”
Volunteers are trained to identify different crab species by counting the number of marginal teeth, which are the jagged edges on their shells, and determining whether their legs have a hairy appearance.
“This is the fun part,” volunteer Kim McCary said as Heffelfinger hauled a trap out of the water and Shirley Hoh prepared to take notes on the crabs.
The first trap they emptied Saturday had 46 crabs. The majority were hairy shore crabs, and all but a handful were males.
The group samples the lagoon once a month at low tide. They started the work in April and will wrap it up in September.
The data they collect is part of a Washington Sea Grant project to monitor for signs of the invasive green crab on the state’s inland shorelines. Washington Sea Grant is a marine research and education program based at the University of Washington.
Identifying the green crabs early can help wildlife managers fight them and reduce impacts to the native environment, as well as help determine how the crabs impact the shoreline habitat after they arrive.
“Basically we’re setting a baseline for the native population and hoping we don’t find an invasive green crab,” Heffelfinger said.
If they do find one, they’re instructed to photograph it and keep it until a wildlife manager can collect it.
“It’s definitely catch and do not release,” Heffelfinger said.
European green crabs were originally found in the northeast Atlantic Ocean and Baltic Sea. They are now found on shorelines around the world including in Australia, Africa and North America.
The crabs are believed to have arrived on the West Coast through water discharges from marine vessels, in seafood shipments and as larvae moved by ocean currents, according to Fish & Wildlife.
Contrary to the name, green crabs are found in a variety of colors, according to the state Department of Fish & Wildlife.
As a predator that can open shellfish, the crab has caused losses for the soft-shell clam industry in Maine and manila clam stocks in California.
With the crab now found on Vancouver Island and in Washington state’s Willapa Bay, it’s of concern for the state’s shellfish industry.
“The green crab could threaten Dungeness crab, oyster, and clam fisheries and aquaculture operations in the Pacific Northwest and British Columbia,” according to the Washington Sea Grant project description.
Taylor Shellfish Farms spokesman Bill Dewey said that’s a concern for them as well as other commercial shellfish growers. Taylor Shellfish operates a farm in Samish Bay.
If the green crabs “become more widespread and common, they could become a problem for us,” Dewey said.
According to the governor’s office, the state is the leading producer of farmed bivalves in the United States, with an industry that brought in $150 million in 2013.
The crabs could also compete with native fish and bird species for food, according to wildlife managers.
“They’re like starlings, they just take over the whole habitat,” Heffelfinger said.
Wildlife managers are preparing for the possibility that green crab larvae may soon move into Puget Sound.
Washington Sea Grant launched a volunteer monitoring program in Puget Sound last year under the leadership Emily Grason of the University of Washington.
During the first round of survey work in 2015, 30 volunteers monitored seven sites and found no green crabs.
This year the project includes 25 sites, one of which is the lagoon adjacent to the Kukutali Preserve.
The lagoon is part of the Swinomish Indian Tribal Community’s tidelands, Grason said. The tribe gave the volunteer team special permission to use the site for green crab research.
Grason said in future years, the project could include additional monitoring sites in Skagit County.
The Washington Invasive Species Council has deemed the green crab one of 50 priority species for the state. That means out of about 700 invasive species the state has analyzed, the crab was among the 50 highest-threat species, council executive coordinator Justin Bush said.
Volunteers and wildlife managers continue to search for the species because once it moves in it may be difficult to contain.
“Invasive species are kind of like a wildfire. You want to get on it immediately before it’s too big to manage,” Bush said.
The Invasive Species Council encourages boaters to avoid transporting water from other areas to prevent inadvertently bringing green crabs into the area and putting shellfish farms at risk.
The public can also help by learning how to identify the invasive green crab.
“If you think you’ve seen something that maybe doesn’t fit in or maybe you’ve never noticed it before, report it to an agency like the Invasive Species Council,” Bush said.
The council takes submissions at 888-268-9219, online and through the mobile phone app WA Invasives.