Volunteers crab for a cause at island estuary

They donned their rubber boots the morning of Sunday, April 27 to wade around Raab’s Lagoon.

By Alex Bruell • April 30, 2025 12:30 pm

A couple of volunteers donned their rubber boots the morning of Sunday, April 27 to wade around Raab’s Lagoon, measuring and counting sea life in a thorough search for any signs of invasive green crabs.

Jeff Adams, a marine ecologist from Washington Sea Grant, a University of Washington-affiliated research program, led the small group Sunday. From their traps, they found plenty of fish and lots of beautiful, vivid-purple graceful rock crabs, which the team carefully counted, determined sex, measured and released back into the lagoon — all while avoiding the crab’s pinching claws.

Good news: No invasive green crabs — which ruthlessly outcompete local species and destroy seagrass and fish habitat while hunting and burrowing — were spotted. The species already poses a threat to Alaska’s fisheries industry, and the crabs have now made it to Washington. Former Gov. Jay Inslee issued a state of emergency in January 2022 to combat the infestation.

“We don’t want them,” said Nancy van Roessel, an island resident with a biology background and one of the two volunteers at Raab’s Lagoon. “Those things are bad news.”

Early detection is key, so researchers set traps in areas that would be attractive to the animals. KVI Beach and Raab’s Lagoon are both monitored by researchers; the unusual topography of the latter makes it an attractive place to feast for water birds and crabs. It could be great habitat for green crabs to gain a foothold, according to Adams and the volunteers.

“This sort of location is ideal,” van Roessel said. “If a green crab larvae ever gets in here, they’ll thrive, although they don’t have any Dungeness crabs for them to eat. … That’s why the clam and Dungeness crab people, they’re the ones terrified of green crab invasion.”

In the meantime, the traps help researchers get a sense of other animals and how rapid temperature shifts or other conditions affect them. “Since we hope to never find them [green crabs], we also want to collect background data on the [other] species here long-term,” Adams said.

Regular folks can help researchers detect a green crab invasion early by learning to identify and report the crustaceans and their molts while strolling the beach. For more information, and to sign up for a training workshop, visit wsg.washington.edu/crabteam.