Editor’s note: this article contains new clarifications from resource managers. -MD
After more than six years of being removed from the North Olympic Peninsula, it seems European green crab will continue to find unwelcome homes in Clallam and Jefferson counties and across Washington state this year.
Captures of the invasive species — linked to destroying eelgrass habitat and out-competing native species such as Dungeness crab — remained relatively small in Sequim and Dungeness throughout 2022.
However, resource managers found the invasive crab in Discovery Bay in August for the first time and over several months trapped 76 green crabs.
In Neah Bay, totals went up 20-fold between 2021 to 2022.
According to marine ecologist Adrianne Akmajian for Makah Fisheries Management (Makah Tribe), staff and volunteers captured 26,140 green crabs last year, a number that far surpassed their previous high.
“It sort of started to feel like they were everywhere,” she said.
One trap captured more than 100 green crabs.
“I’ve never seen that before,” Akmajian said. “Last year, we had 33 in a trap.
“Now we’re splitting hairs sometimes, asking, ‘Where do we want to do trapping?’ Some traps are getting 50 to 90 crabs at a time, and some are getting 20 to 30, so we do the areas with 50 to 90 per trap.”
Statewide, at least 269,579 European green crabs were removed from Washington waters in 2022 by multiple partners and agencies, according to Washington Department of Fish and Wildlife staff.
Growing captures of green crab led to an emergency proclamation by Gov. Jay Inslee for Fish and Wildlife staff to eradicate or prevent establishment of the crab. This led to additional funding that helped add staff, traps and research statewide.
The Makah Tribe was one of recipients of state funds with Akmajian saying they had six staff (full-time and seasonal) at the busiest trapping juncture.
Neil Harrington, an environmental biologist for the Jamestown S’Klallam Tribe, has been checking and trapping Sequim Bay for green crab for a handful of years.
In 2022, he caught two green crabs with about 800 traps compared to 16 captures in 2021. His efforts focused more in the late summer/early fall to Discovery Bay where he and Fish and Wildlife staff found green crab too.
He said in Discovery Bay, near the intersection of U.S. Highway 101 and State Route 20, they captured 76 green crabs between Aug. 3 and Oct. 11 in/near Snow and Salmon Creek Estuary.
Harrington said some of the crabs were larger with about two-thirds of them female (with no eggs), so they could have been established there for some time.
Marine ecologist Emily Grason, Crab Team program lead for Washington Sea Grant, said trapping revealed no detections in previous years, including at an ongoing Crab Team monitoring site.
“So far, crabs appear to be most densely concentrated in two creeks flowing into the head of the bay, as well as a recently restored lagoon,” she reported.
Grason wrote in a later email that the area’s catch rate of 12 green crabs per 100 trap sets is on par with the highest observed catch rates anywhere inland excluding the Lummi Sea Pond, a human constructed feature west of Bellingham where 70,000 crabs were captured in 2021.
“As such, (Discovery Bay) is a significant concern as an establishment risk,” she reported.
For this year, Harrington said they’ll continue trapping in Discovery Bay and Sequim Bay.
“I’m somewhat optimistic that we can keep them from exploding in Puget Sound,” he said.
Grason reports 17 green crabs were found from 622 trap sets in Seabeck in 2022, as well.
At the Dungeness National Wildlife Refuge, 14 European green crabs were captured this year through trapping led by the U.S. Fish and Wildlife Service.
Deputy project leader Lorenz Sollmann said they’ll set 800-plus traps at low tides from April to September at three locations — the Base Lagoon, Graveyard Spit Channel and the East Lagoon.
Chase Gunnell, Washington Fish and Wildlife’s Puget Sound region communications manager, said Washington Sea Grant’s Crab Team maintained eight other monitoring sites on the northern Olympia Peninsula this year, capturing one European green crab in Dungeness’ Base Lagoon.
“We at (Fish and Wildlife) are relieved to see that European green crab captures did not increase significantly in the Strait of Juan de Fuca management area this year, and that no new hotspots emerged,” he said.
In Neah Bay, Akmajian said green crab captures were mostly in the Tsoo-Yess River and Wa’atch River with some found in rocky intertidal waters but none in Neah Bay itself.
Of the 26,140 crabs caught, 2,483 were by hand, she said, and the remainder captured from 2,863 set traps.
“We’re projecting another really big year,” Akmajian said. “Even in the winter, we’re setting a couple traps in each river and we already have over 40 (green crabs) in the books (for 2023).”
One trend that concerned her was seeing more smaller crabs later in the trapping season that they needed to catch by hand due to their size. Staff are building some sampling devices to try to capture juvenile crabs, she said, and they’ll be analyzing underwater video to see how green crabs interact with other crab species.
Makah Fisheries staff also marked and recaptured 1,5000 Dungeness and 500 green crabs last year and discovered some were swapping rivers.
Three green crabs traveled about a mile-and-a-half to one river or the other, Akmajian said.
Why they’re moving so far could be due to the tides, food and other factors, she said, and of concern is that if three of the 500 marked green crabs moved rivers, then even more could be moving into new, unknown habitats. One of three was a female with no eggs, she said, but researchers say one female can release up to half-a-million larvae per brood with the possibility of more than one brood per year.
Looking ahead, she thinks “now, more than ever, there’s a continued concern for (green crab) damaging natural resources and habitat.”
“Now there’s much more of a need to knock down the big numbers,” Akmajian said.
If you suspect you’ve spotted a European green crab, visit wdfw.wa.gov/greencrab.