the green crab - invader of our coastal systems

The Green Crab - Invader of our Coastal Systems

THE GREEN CRAB (Carcinus maenas)

An aquatic invader

The green crab invaded the coast of North America more than a century ago (probably during the 1850s).

By the 1950s, it had colonized the waters of New Brunswick. It is likely that it invaded British Columbia in 1998 through warm tidal currents due to El Niño.

The green crab preys on native crabs, clams, oysters, and mussels and occupies their habitat. It also eats the same food as crabs, lobster, and many seabirds.

A single green crab can eat 40 clams in a day. Green crab are thought to be a serious threat to eelgrass (Zostera) beds.

(Based on research undertaken by the Biology Department at St. Francis Xavier University by Dr. Garbary and Dr. Williams.)

This is how Green Crab can affect the environment

Green Crab numbers can explode

so that they eat everything

There are no natural predators

to control their numbers

What Can You Do?What Can You Do?

Before trailering your boat:- Wash boat, anchor, trailer and other equipment with fresh water and/or

spray with undiluted vinegar. - Remove any plants or animals. - Drain water from your boat motor, bilge,

and wells. Let equipment dry completely, if possible.

For larger vessels:- Use anti-fouling paint to reduce settlement

of organisms on the hull. - Don't take on or release ballast water in

port, near aquaculture facilities, or at night.

What Can You Do?What Can You Do?

Never release live bait, aquarium fish, crayfish, or Never release live bait, aquarium fish, crayfish, or plants into the water. plants into the water.

Clean clams or other shellfish in the water where they were collected. Move them with a minimum amount of water.

Learn to identify invasive species in your area and Learn to identify invasive species in your area and report any sightings. report any sightings.

Ocean Food Web

For Additional Information Contact:

Ray MacIsaacOceans and Habitat DivisionFisheries and Oceans CanadaCharlottetown,  P.E.I. C1A 7M8  phone: (902) 626-2934 cell: (902) 393-1975     macisaacr@dfo-mpo.gc.ca 

Or any DFO office in your area