Angry mutant green crabs are destroying everything in their path

FILE – June 6, 2018, file photo shows a green crab in Portland, Maine. The University of New England researcher said green crabs migrate from Nova Scotia are ornerier and angrier than their Gulf of Maine cousins. (AP Photo/Robert F. Bukaty, File)

(Copyright 2018 The Associated Press. All rights reserved.)

Talk about being cranky.

Angry green crabs from Nova Scotia, angrier than the usual green cousins in Maine, the migration from the south. They began with the destruction of the coastal ecosystem off the coast of Maine, if they eat more than their share of the soft-shell clams and wreck native eel grass, according to research from Markus Frederich, a professor at the University of New England.

“What we see is this insane level of aggressiveness,” Frederich told the Associated Press.


Although green crabs are related, they are genetically different from each other. The evil Nova Scotia crabs have their roots in the north of Europe and have adapted to the cold water, while the quieter Maine version came from the southern part of Europe.

She performed for the first time in the V. S. in the middle of the 1800s, according to the Washington Dept. of Fish & Wildlife. After arriving in Maine in the 1950s, they caused a soft-shell clam decline and eventually make their way to Nova Scotia.

“The green crab is often confused with native helmet crabs or hairy shore crab,” the Dept. of Fish & Wildlife wrote on its website. “The most striking feature is not its color that can vary from red to dark mottled green – but the five spines or teeth on each side of the shell. There are three rounded lobes between the eyes, and the last pair of legs somewhat flattened. The carapace is wider than it is long, and rarely exceed 3.5 to 4 inches diameter.”

Louis Logan, a University of New England student, was the unpleasant task of tagging the crabs caught from Nova Scotia for the research. The crabs were not in the mood for games.

At a distance of 5 metres, the pint-sized brutes assumed a fighting stance. Who grabbed him had let go.

“Every time I went downstairs to grab they went to grab me instead,” he wrote in an e-mail.

One of them, in particular, would jump out of the water in its rage attack.


During the research, both sets of green crabs were unleashed on a bed of eel grass, and the Canadian species destroyed, Frederich comparing the damage to that of Edward Scissorhands, as she tried to look for marine organisms to eat.

Green crabs are known to be particularly disruptive to the existing ecosystem. The University of Washington has given some tips on what to look for and what to do if they are to be found.

Additional research will be done in the coming months to decipher whether a particular gene plays a role in the aggressiveness, or as a factor referred to as hybrid vigor in the game, Frederich said. The hybrid vigor theory suggests that the crabs can be aggressive if they establish themselves, but mellow out later.

The quarrelsome newcomers currently comprise only about 2 percent to 3 percent of the green crabs crawling on the ocean floor off Maine, but those numbers are certain to grow, Frederich said.

“It will be a very different ball game,” he predicted. “It’s just a question of when more of the crabs coming and out-compete the Maine green crabs.”

Eventually, the newcomers go further south. “We can do nothing about it,” he said. “The only thing we can do is learn how to live.”

The Associated Press contributed to this report. Follow Chris Ciaccia on Twitter @Chris_Ciaccia

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