As local European green crab totals stayed relatively low in 2021, the Sequim-Dungeness area remains centered between growing infestations from Neah Bay to Whatcom County.

Sequim’s population of the invasive species was a fraction of those found in the Lummi sea pond west of Bellingham where more than 70,000 green crabs were captured. In late November, the Lummi Indian Business Council declared a disaster with Washington Sea Grant’s Crab Team reporting it to be Washington’s largest infestation along inland shorelines.

In comparison, resource managers with the Washington Maritime National Wildlife Refuge in Dungeness and Jamestown S’Klallam Tribe at Sequim Bay reported 24 combined captures (eight and 16, respectively) last year.

Green crabs, known by their five spines on the side of each eye, were first detected on the Lummi Reservation’s pond in 2019 and counts jumped from 41 to 2,670 in 2020 to more than 70,000 in 2021, Washington Department of Fish and Wildlife reported.

While the number is large, Dr. Emily Grason, marine ecologist and Crab Team program lead, and Bobbie Buzzell, lead biologist for Lummi Natural Resources, report that resource managers detected no major range of green crab expansions in 2021.

“The only places green crabs were captured were generally sites and water bodies with a known presence of European green crab in previous years,” they reported.

At the Lummi sea pond, Grason and Buzzell say it’s “an ideal incubator” due to its shallow waters, its minimal connectivity to tides, and lack of predators. However, resource managers are concerned that larvae could leak out into the Salish Sea and spread to neighboring areas so tribal leaders plan to continue researching and trapping with state, tribal and other partner agencies.

Grason said in previous interviews green crab larvae can travel as far as of 100 kilometers, and a female can release up to half-a-million larvae per brood with the possibility of more than one brood per year.

Representatives with the Makah Fisheries Management, Angelina Woods, left, and Adrianne Akmajian, hold up the first European green crab captured last year in April. The Makah Tribe would go on to catch more than 1,400 green crab, their most ever. Photo courtesy Adrianne Akmajian/ Makah Fisheries Management

Olympic Peninsula

In Neah Bay, Adrianne Akmajian, a marine ecologist for Makah Fisheries Management, reports she and her team caught 1,460 green crabs in 2021 through various methods, their most ever in a year since trapping started in 2017.

Controlling the numbers, she said, is important to the Makah Tribe “to protect native species and habitats, including shellfish like clams that are harvested for subsistence and coastal and nearshore eelgrass beds that are important nursery habitats for a variety of species, including salmon.”

“Green crabs can compete with other native species utilizing the rivers and nearshore waters, such as juvenile Dungeness crabs, which may impact tribal fisheries,” Akmajian said.

“Regionally, it is really important to try to limit the numbers of crabs to reduce the chance of local reproduction and larvae or crabs being spread from the Reservation down the coast or into the Strait.”

In Dungeness, captures were slightly up from 2020, with three crabs from more than 1,800 traps to eight crabs in 2021 with 839 traps placed, reported Lorenz Sollmann, deputy project leader at the National Wildlife Refuge.

“With so few crabs caught for a second year in a row we might be able to scale back a little more in the channel on Graveyard (Spit) like we did at the base lagoon,” Sollmann said. “Last year we only did the monthly monitoring there and for a second year caught no green crabs.”

Green crabs were first detected in Dungeness in 2017 after years of monitoring with 96 green crabs caught and then declining to 69 in 2018 and 57 in 2019. Grason said none of the crabs there in 2021 were “young of the year, which is hopeful news for continued low numbers of crabs next year.”

Photo courtesy Neil Harrington/Jamestown S’Klallam Tribe Along Sequim Bay, Neil Harrington, environmental biologist for the Jamestown S’Klallam Tribe, reported 16 green crab captures after placing 963 traps through early November after not catching any green crabs in 2020.

Along Sequim Bay, Neil Harrington, environmental biologist for the Jamestown S’Klallam Tribe, reported 16 green crabs in 963 traps through early November after not catching any in 2020.

“While the total is still smaller than some other sites, and the capture rate is relatively low, the increase compared to previous years is large enough to raise concerns,” Grason said.

Harrington said he plans to continue trapping in Sequim Bay’s south end marshes.

“I would imagine the level of effort will be similar to 2021, maybe a bit higher since we will start earlier in the season,” he said.

In Jefferson County, Grason reported that staff with the Department of Fish and Wildlife captured two green crabs by Bishop’s Point last May but no others were found at nearby sites.

With a slight increase in detections between Sequim and Jefferson County, Grason said “the Strait of Juan de Fuca provides a semipermeable barrier to dispersal of larvae into the Salish Sea from coastal waters.”

“However, we know from both genetic and ocean modeling evidence that occasional reversals of surface water flow can carry green crab larvae into the Salish Sea, particularly along the southern shoreline of the Strait,” she said.

“Even if these reversal events are relatively infrequent, recent dramatic population increases in coastal estuaries of Willapa Bay and Grays Harbor might provide enough of a boost to the number of larvae in the surface water during the time of year that reversals occur, that we could be starting to see the carry over of coastal populations to inland shorelines.”

Grason added that the local numbers “are still very low compared to anywhere on the coast, or other inland hot spots like Lummi sea pond.”

Future measures

COVID-19 restrictions and shut downs led to limited green crab trapping throughout the summer and fall of 2021 for the Makah Tribe, Akmajian said.

But she said she’s optimistic efforts will increase this year with more secured and potential funding for staffing and equipment.

“Already we have plans to conduct weekly, instead of bi-weekly trapping during the peak season and to include setting traps in marine waters in (more areas),” Akmajian said.

Regular trapping occurred from April-June and mid-September to mid-October between the Tsoo-Yess River, Wa’atch River and near Tsoo-Yess Beach.

During the year, her team hand-caught 99 green crabs less than 20 millimeters in size with larger accumulations in May, June, July and October, which she said “implies that we may have had as many as four different settlement events of young 2021 crabs settling into our estuaries.”

Makah tribal staff also saw their highest catch rate in October with 350 crabs caught over two days, she said.

With other funding, Akmajian conducted research and monitoring of a mark-recapture experiment of crabs, and of underwater video of interactions between green crab and Dungeness crab, which she plans to do again later this year, too.

Washington Sea Grant continues a network of 55 early detection/monitoring sites along inland shorelines in 2022, including Pysht (one site), Dungeness Bay (four), Sequim Bay (two) and Discovery Bay (one) along with newer sites in coastal estuaries, such as Makah Bay monitored by tribal, agency and shellfish growers, and volunteers.

She and Buzzell also report the Lummi Nation’s leadership are coordinating with multiple partners to increase trapping and removal efforts along with creating strategies to limit growth and spread of green crab.

Fish and Wildlife staff report they are coordinating stakeholder meetings this year for Western Washington to work together to control the species, too.

Resource managers say if you find a green crab or its shell, report it online to crabteam@uw.edu, but leave it in place.

For more on crab identification, visit wsg.washington.edu.

Photo courtesy Adrianne Akmajian/ Makah Fisheries Management The Makah Tribe captured more than 1,400 European green crab in 2021. They look to prevent the invasive species from depleting natural habitats and outcompeting local species.

Continuing this year, staff with Makah Fisheries Management plan to continue underwater research of interaction between Dungeness crab and the invasive European green crab. Photo courtesy Adrianne Akmajian/ Makah Fisheries Management