Invasive European green crabs are continuing their long march northward.
A researcher with the Department of Fisheries and Oceans (DFO) confirmed two females of the species have been found at Esquimalt Lagoon.
“This is the first that it’s been found, to our knowledge… ever in Esquimalt Lagoon,” said Patty Menning, an aquatic invasive biologist with DFO.
“We looked at 28 potential sites last year that may be suitable for green crab. And this year we’re continuing that program, and we are looking at other sites within the Salish Sea,” she said.
Menning and members from a community group recently deployed around 90 traps at the Esquimalt Lagoon, a wildlife sanctuary home to migratory birds, to eradicate the species.
“We use two different types of traps to try to target both the adult and the juvenile stages of European crab,” she said.
The crabs have a higher tolerance to increased temperatures and decreased salinity than native ones. That means they can survive in places that native crabs such as red rock and Dungeness can’t occupy, Menning said. They have been spotted on the west coast of Vancouver Island, including along Sooke Basin.
European green crabs compete with the native juvenile crabs for prey such as bivalves, worms and smaller crabs on the shore. “They’re actually competing with our native population. As well, they’re voracious eaters,” Menning said.
Their Latin name, carcinus maenas, means “raving mad crabs,” she said.
Reaching up to four inches in size, they were first found on the Oregon coast “back in the ‘60s,” Menning noted. Sometime around 1989, the green crabs were spotted in B.C. waters for the first time, she added.
Menning is running an early detection program for the second summer this year, focusing on the Salish Sea with the hopes of eradicating the population, with traps, before they become established.