Metlakatla leading Alaska's efforts against invasive green crabs

Forty people spread across the estuarine beach of northwest Tamgas Harbor to study the invasive European green crab that's been moving into the large bight on the southern shore of Annette Island since at least July 2022.

For two days the last week of April, a cohort of scientists, resource managers and community members who want to quash the spread of the insidious green crab gathered in Ketchikan and visited Annette Island Reserve to share information about the crab's recent invasion in southern Southeast Alaska waters.

A team of organizers and facilitators from federal and state agencies as well as municipal, state, federal and tribal governments spent about five months putting together the workshop so that folks from across the region could learn about the crab's characteristics and work toward a coordinated regional response.

The invasive green crab is a destructive predator that can change and degrade habitat and threaten native species. The crab adapts well in almost any habitat, and has boomed on the coast of Oregon, Washington and British Columbia in recent years, tearing up essential fish habitat such as eelgrass and devouring clam beds while moving ever farther north. The crabs spread from their native Europe to North America in the 1800s by riding in the ballast water of cargo ships.

Metlakatla Indian Community established an early detection crab trapping system around Tamgas Harbor in 2020, with support from the National Oceanic and Atmospheric Administration. When a team of Metlakatla scientists hosted NOAA personnel for a visit to Tamgas Harbor in July 2022, a visiting Sealaska Heritage Institute student intern named Natalie Bennett found the first-ever evidence of green crabs in Alaska waters.

Bennett spotted the top shell, or carapace, of an invasive crab that had been blown into grasses near a newly placed informational sign that warns: "Look Out! For invasive green crab." One week after Bennett found that first carapace, the team found their first live green crab in a baited pot set inside of a traditional Tlingit salmon trap on a beach in Tamgas Harbor.

The Metlakatla Indian Community team has embodied strategies that workshop leaders shared with participants last month. Organizers demonstrated early detection methods such as identifying and recording crab species in beach surveys of carapaces and dead carcasses, and rapid-response techniques such as systematic trapping for live crabs.

Participants learned to identify the crab by counting five spines on either side of its eyes and three rounded lobes between its eyes. "Green" crabs can be green, dark brown, yellow, white, red or mottled.

When the workshop group arrived at Tamgas Harbor, smaller groups broke off to learn about surveying and trapping protocols through different beach activities.

A small group of workshop participants found two male and one female green crab while checking the first three square shrimp pots out of dozens planted in prime habitat across the long tidal beach. The pots that brought in green crabs were set in a deep eelgrass bed in a tidepool for three days and nights, and were baited with herring.

Taylor Stumpf and the Metlakatla Indian Community Department of Fish and Wildlife crew have been on the front lines fighting the crab's invasion. Stumpf said the crew had not caught any of the invasive crab for over a month leading up to the workshop. The workshop group visiting Tamgas on April 24 recovered the first live crabs found on Annette Island since March 13, according to Stumpf.

"Once you see the green crab, especially in a pot with Dungeness crab, you realize that they stick out like a sore thumb," Stumpf said. "They behave differently, they look so different."

"He explained, "We thought it would be especially valuable to have people come here to Annette Island, the only place in the state where these crabs have been found so far, so that people could actually see the environment and see the crabs themselves."

For an effective regional response, Stumpf said that community members need to have a good handle on how to detect and trap these crabs.

"A lot of the surrounding communities here, especially on southern Prince of Wales Island, don't have their own Fish and Wildlife department and will likely rely on citizen science for monitoring and reporting of invasive species," Stumpf said.

People from nearby Prince of Wales who work for municipal and tribal governments such as the city of Hydaburg, Hydaburg Cooperative Association, the Organized Village of Kasaan and Craig Tribal Association joined in the workshop to study species that could soon threaten their shores.

People who work for the Organized Village of Kake, Petersburg Indian Association, Ketchikan Indian Community and Central Council of Tlingit & Haida joined the workshop. Others who attended work for organizations such as Southeast Alaska Tribal Ocean Research, the U.S. Forest Service, U.S. Coast Guard and University of Alaska Southeast Ketchikan campus and College of Fisheries and Ocean Science in Juneau.

Some came because they lead tour companies.

Many workshop attendees share an interest in food sovereignty and expertise in resource protection. The green crabs could threaten important traditional and subsistence foods as they damage nursery habitat for fish and compete with or consume other shellfish.

"We wanted to really lay the foundation," Stumpf said. "What is this crab, what does it do, how do you identify it, where could you find it?"

Organizers explained the state's permitting process for crab trapping and offered one-on-one support to file permit applications for people who want to monitor for green crabs with their trapping systems.

Workshop leaders demonstrated that communities don't need to invest in expensive equipment in order to detect the presence of green crab on their shorelines.

"The big message I wanted the small communities to take away was that carapace and molt surveys are a great and powerful way to begin," Stumpf said.

While on the Tamgas beach, participants practiced these carapace and molt surveys with Linda Shaw, a workshop organizer who works for NOAA as a habitat conservation biologist. She said she has become "obsessed" with invasive species such as green crabs.

Emily Grason of Washington Sea Grant helped people identify favorable green crab habitat in Tamgas Harbor, such as log jams and protected tidepools. Grason shared stories from years trapping droves of the invasive crab off the Washington coast.

Genelle Winter, the Metlakatla Indian Community grant coordinator and invasive species program director, said the community is leveraging its unique position and funding sources to lead the way with Alaska's green crab response.

"This is going to be a long-haul project and so we are going to have to make sure that everybody engaged in monitoring really cares," Winter told the group during presentations in Ketchikan. "We have to know that all of the data that we are collecting is absolutely essential and valuable to helping us to preserve the natural resources that we've got."

As the workshop closed, Metlakatla Indian Community Mayor Albert Smith addressed the workshop group.

"Our subsistence use, our commercial fisheries, it's all in jeopardy," Smith told the group.

He underscored how the species has exploded in Washington waters. According to NOAA information, more than 102,000 crabs were caught in the Puget Sound and along Washington's coast in 2021, a 5,500% increase from the 1,800 crabs found two years earlier in 2019. Off British Columbia, over 300,000 green crabs have been caught since November 2021 on West Vancouver Island alone.

"Turning a blind eye or acting like it doesn't exist will be a bigger problem, and it will cost more money down the stretch," Smith said.