New Brunswick

Researchers study spike in green crab numbers

Researchers are trying to gauge how many invasive green crabs are living along New Brunswick's east coast.

Green crabs are viewed as one of the world's worst invasive species

Researchers are trying to gauge how many invasive green crabs are living along New Brunswick’s east coast.

The Fisheries and Oceans Canada has said the green crab is migrating north and has been found as high as Neguac.

Traps are set along the coast to see if there has been an increase in the population of green crabs.

Jim Weldon, a member of the Shediac Bay Watershed Association, said the organization’s beach seining program saw a significant increase in the number of green grabs in the area.

Weldon found seven in a trap two years ago, then last year he collected 550 in a trap.

"That sort of was an eye opener, a trigger to explore this a little further the problem with the green crab is if they, if they do get to the point where they explode they can have a very detrimental effect on local habitat, especially local fish habitat," he said.

The green crab is a 10-centimetre-long invasive species from Europe. It was first spotted in New Brunswick in the Bay of Fundy in the 1950s.

The species was first introduced on the northeastern seaboard in the early 19th century and migrated north from there. It has since worked its way around Nova Scotia towards the Northumberland Strait.

The green crab eats oysters, mussels and clams. They are also known to eat large quantities of the shellfish seeds used in the aquaculture industry.

Weldon said he’s concerned about the destructive nature of the crabs.

"They have a tendency to completely destroy the habitat, by digging up the eel grass looking for the crustaceans, which is one of their main sources of food," he said.

"They'll eat anything, you put anything in front of them and they'll eat it."

Weldon said he will be setting traps in Shediac Bay next week.

Julie Cormier, the executive director for Vision H20, a watershed group in the Cap-Pelé and Beaubassin East region, said she’s already checking green crab traps in her area.

"When we take our samples, like, there's only maybe five or six and last year there was maybe 10 or 12, but it doesn't mean the numbers from all the bay or the estuary are going down," she said.

Even if the numbers are easing off, Cormier said the crabs are here to stay.

According to Fisheries and Oceans Canada, the green crab is ranked among the 100 worst alien invasive species worldwide.

It is an aggressive competitor and a prodigious reproducer that is tolerant of a wide variety of marine environments, with the ability to alter entire ecosystems at great economic cost.