Reprductive green crab Female green crab Trapping

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Reproductive green crab, courtesy of Linda Shaw

Female green crab, courtesy of Lina Cabellos.

Trapping in Glacier Bay, coutesy of Linda Shaw

Welcome volunteer monitors!

On this site you’ll be able to find information about the invasive European Green Crab, Carcinus maenas, download sampling protocols, upload monitoring data, search monitoring data from other users, and communicate with coordinators and other monitors through the online forum.

European Green Crabs

European Green Crabs have made the list of 100 worst invasive species due to their impacts on communities in invaded regions. Green crabs prey on and compete with other crabs, bivalves (clams, mussels) and gastropods (snails, slugs) and have had major economic impacts on New English shellfisheries.

Green crabs are native to Europe from Iceland and Norway to Mauritania, West Africa but have been very successful invaders globally. They are now found on five continents including regions of the Northwest Atlantic (from Maryland-Newfoundland), the Southwest Atlantic (Patagonia), the Southeast Atlantic (South Africa), the Northeast Pacific (from California-British Columbia), the Northwest Pacific (Japan) and the Southwest Pacific (Australia). They tend to be most abundant in sheltered intertidal and shallow subtidal habitats. A complete history of the spread of green crabs with detailed maps can be found in NEMESIS (National Exotic Marine and Estuarine Species Information System).

Monitoring Effort

The Smithsonian Environmental Research Center began efforts to monitor for green crabs in Alaska in 2000. Currently trapping is done in Kachemak Bay, Prince William Sound and in Southeast Alaska and is a cooperative effort overseen by the Kachemak Bay Research Reserve, Prince William Sound Regional Citizens Advisory Council, and National Marine Fisheries in Juneau. Where possible, monitoring occurs monthly throughout the summer months at each site.

If you are interested in becoming a monitor check out the ‘Join Us' tab for more details, contact the coordinator in your area or Linda McCann at mccannl@si.edu.