Keep trapping or not: that’s the dilemma facing the Makah Tribe in Neah Bay.
The tribe’s totals for European green crab, an invasive species known for edging out local sea life such as Dungeness crab and eelgrass beds, have surpassed the high mark from last year.
From April 1 to Oct. 2, Adrianne Akmajian, a marine ecologist with Makah Fisheries, and her crews caught 1,262 green crab between the Tsoo-Yess River, Wa’atch River and near Tsoo-Yess Beach. That’s more than 20 times the Sequim area’s totals, an area that in 2018 shared with Neah Bay the distinction of having the largest totals for European green crab captures across the Salish Sea.
Last year, the Makah Tribe captured 1,030 green crabs.
Akmajian said funding is in place to continue trapping next year, but she questions the level to which they’ll continue their efforts.
“It’s unlikely we’d eradicate them, but we can keep monitoring,” she said. “We have some ideas to do studies to track crabs. So for at least one more year, we’ll keep operating with trapping.
“We’re wondering if this is the new normal.”
They won’t begin trapping again until next spring
Akmajian wonders if their numbers are higher because they’ve gotten better at trapping, such as using shrimp traps in larger river channels.
Akmajian said she sent green crabs for DNA analysis again to see where they might be coming from.
Of the crabs analyzed in 2017, she said most were from the outer coast. However, depending on the oceanographic conditions, they could have come from any direction, she said.
Local studies in Neah Bay continue of river otter scats to see if they’re eating green crab, Akmajian said, which could offer some local, natural mitigation.
Sequim-Dungeness
While Neah Bay’s totals climb, the Dungeness Spit appeared to have hosted fewer green crabs than last year.
Lorenz Sollmann, deputy project leader at the Washington National Wildlife Refuge in Dungeness, said his crews captured 57 green crabs this season, a decline from 69 in 2018 and 96 in 2017, when green crabs were first discovered there.
Sollmann said resource managers set 2,444 traps over 70 trapping days with a standardized catch-per-unit effort of 2.37 for 2019, compared to 2.55 and 2.56 the previous two years.
Neil Harrington, environmental biologist for the Jamestown S’Klallam Tribe, caught two green crabs in Sequim Bay this season as well.
Sollmann said he plans to continue trapping again in April 2020. Resource managers began preventative trapping in 2001 along the Dungeness Spit but nothing was discovered until 2017.
Jefferson County
No European green crabs were found in Jefferson County this year.
Two were found in East Jefferson County in 2018.
When volunteers with Washington Sea Grant’s Crab Team spotted a 77-millimeter male green crab at Kala Point Lagoon during routine monthly trap sampling Sept. 8, 2018, it was the first green crab captured there since survey trapping began in 2015. Another was found that year at Scow Bay between Indian and Marrowstone islands.
Despite ongoing trapping near those areas this year (Scow Bay is currently undergoing bridge construction) no green crabs have been detected there since late last year, said Emily Grason, marine ecologist and Crab Team program manager for Washington Sea Grant.
Growing population
In September, resource managers reported additional captures this season including four in Samish Bay, five in Whatcom County and one on the San Juan Island.
Following early evidence of green crabs in Drayton Harbor near Blaine, resource managers with the Washington Department of Fish and Wildlife and the Washington Sea Grant Crab Team trapped 17 green crabs during a two-day rapid response in late September.
Resource managers said this is the largest number of green crabs trapped in a short period of time along Washington state’s inland shoreline.
“Finding this many invasive green crabs so quickly in one area raises a serious concern that there may be an established and reproducing population in Drayton Harbor,” said Allen Pleus, Fish and Wildlife’s aquatic invasive species manager.
Since then, Fish and Wildlife have found another 21 green crabs at Drayton Harbor and plans meetings to discuss an ongoing response.
Grason compared managing green crab to preventing wildfires.
“We keep a sharp lookout and respond quickly to small populations before they get too big to control,” she said.
“When even a single green crab is found, the first step is to quickly do more trapping to figure out the size and geographic extent of a potential population,” she said.
”Then we have more information to determine the best way to manage them.”
Grason said this time of year is the end of the trapping window because as the weather becomes colder, green crab are less likely to go for traps.
Between now and next trapping season, Grason said Fish and Wildlife plans to host two stakeholder meetings in the Sequim area and along the Interstate 5 corridor to discuss efforts, share information and work out management strategies.
Crab Team’s core funding is secured through June 2021 through the state, as it continues to coordinate early-detection monitoring sites across Western Washington, including the Lower Elwha Tribe at the Pysht River, Dungeness Landing, Washington Harbor and Jimmycomelately Creek in Sequim Bay and Discovery Bay, and Kala Lagoon and Indian Island in the Port Townsend area.
Beginning trapping
European green crab were first trapped on the West Coast in San Francisco Bay in 1989 and later confirmed in Washington waters in 1998 in Willapa Bay and Grays Harbor.
Fish and Wildlife staff partnered with Washington Sea Grant in 2012 to develop the early detection monitoring program after a large discovery of green crab in Sooke Basin on Vancouver Island.
Trapping in Neah Bay began in 2017 after a passer-by discovered a green crab near the Wa’atch River and reported it to Washington Sea Grant, leading to intense trapping efforts resulting in 34 green crab.
Resource managers said those who find a live green crab or its shell in Washington should report it online to crabteam@uw.edu, but leave the crab in place to avoid accidentally killing native crabs.
It is illegal to possess a live green crab in Washington to protect native crabs from cases of mistaken identity.
For more information about crab identification, visit wsg.washington.edu.
For more about aquatic invasive species, visit wdfw.wa.gov/species-habitats/invasive.
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Matthew Nash is a reporter with the Olympic Peninsula News Group, which is composed of Sound Publishing newspapers Peninsula Daily News, Sequim Gazette and Forks Forum. Reach him at mnash@sequimgazette.com.
