Dreaded green crab found in Burnt Islands

By Mandy Ryan

FOR THE SOU’WESTER

Fred Thorne trapped something different in his lobster pot last week, something he hopes to never catch again.

"They're the real devils. They're vicious," said Thorne of Burnt Islands, the first known lobster fisher to have caught a green crab on the southwest coast.

At just three and a half inches across the back and green in colour, the foreign crab is native to warmer waters, believed to have hitch-hiked overseas in ballast tanks of huge freight ships.

A DFO study is ongoing in Prince Edward Island where green crabs have eaten much of the mussels and clams near the shoreline. Little is known about the foreign species except that they have a healthy appetite and that they are aggressive.

"They're fast. They will come right at you. They have eight legs, and they'll stick right up on their ends with their two claws coming right out at you, like two arms coming out at you," described Thorne.

"I had it in five-gallon bucket with water and when I walked into the stage…I thought it was going to come right out of the bucket. That's how smart they are,” Thorne said. “It just came right up to the top…I put it on the stage floor and it ran right across the stage floor and crawled under a piece of plastic as if it knew it was there. It's unreal."

According to the Department of Fisheries and Oceans, the green crab is invading Canada's coasts, ruining prime habitats for shellfish stocks and nurseries for juvenile fish by its burrowing, and eating just about everything that lives in its new home.

Thorne said to identify them one must count the number of spines on their sides. They have five starts on each side.

"They told me that's how you know it's the real thing, and this one is the real thing," he said of the crab he caught.

Advice from the DFO about the crab included keeping it out the water in case it is female and has live eggs.

DFO says the green crab has been a pest in the Maritimes from as early as the 1950s, and since the late 1990s on the West Coast.

They were reported for the first time in Newfoundland at North Harbour in Placentia Bay last August. Within days of the report, an 11-person DFO team went to Placentia Bay to determine the extent of the infestation. They found North Harbour was completely taken over by green crabs. There were no other crabs and no juveniles of any species to be found. An empty clam bed had only depressions marking where the clams had been dug up and consumed by the green crabs.

(Mandy Ryan is the editor of Transcontinental Media’s Gulf News, which is a contributor to the Sou’Wester.)



QUICK GLANCE

Green crab facts, according to DFO science:

•The green crab is aggressive and fast, and has a voracious appetite.

•They eat clams, mussels, oysters, scallops, and possibly young lobsters.

•They have no natural predator in their new home.

•Green crabs are prolific breeders, with females capable of spawning up to 185,000 eggs per year.

•The green crab can burrow into the seabed, damaging the roots of plants such as eelgrass that define the habitat, causing established beds to float away.

•It can rotate its claws over its back, enabling it to defend itself from predators attacking from behind

•It can live out of water for up to a week in full sun.

•It can even survive fresh water, with no problem.

•The green crab has been dubbed the "cockroach of the sea."