European Green Crab

A new program will enable anyone who walks the shorelines of Puget Sound to identify one of Washington state’s most concerning invasive species: European green crab.

In response to this shore crab’s booming population, Washington State University Extension and Washington Sea Grant outreach specialists are rolling out the Molt Search program in May.

Deployment of emergency measures to control invasive European green crabs on the Washington Coast and at sites within the Salish Sea is well underway, including the implementation of an Incident Command System (ICS) to facilitate statewide coordination between various agencies, tribes, and partners.

Washington Governor Jay Inslee has issued an emergency order [PDF, 174 KB] to address the exponential increase in the European green crab population within the Lummi Nation’s Sea Pond and outer coast areas. The European green crab is a globally-damaging invasive species that, if they become permanently established, will particularly harm endangered species, impact resources that are part of the cultural identity of the tribes and native peoples, and affect small businesses.

The green crab is an invasive marine species spreading throughout the coastal waters of the United States. Efforts between NOAA Fisheries and Metlakatla Indian Community have been leading the way on monitoring to detect this species’ presence in Alaskan waters. The green crab has been found in U.S. waters since the 1800s, but this is the first confirmed presence in Alaska. They are a serious threat for Alaska’s tidal habitats.

If you see an invasive green crab on Annette Islands Reserve, call (907) 886-FISH to make a report. If you encounter a potential green crab elsewhere in Alaska, take photographs from multiple angles and send them to Tammy Davis. Then submit a report to the Alaska Invasive Species Reporter, or call the Invasive Species Hotline: (877) INVASIV.

European green crabs are one of the most widespread invasive marine species on the planet, originally reaching Washington in 1996. When green crab populations grow too large, they compete with other shellfish, disturb the sediment, and destroy the eelgrass that is an important habitat for Dungeness crab and salmon. The U.S. Geological Survey (USGS) is working to increase the effectiveness of Washington’s green crab early detection and rapid response program. Research conducted at the USGS' Western Fisheries Research Center aims to improve native shellfish habitat and limit the spread of European green crabs in coastal waters.

In early December Washington Department of Fish and Wildlife (WDFW) Police received information that a Seattle market was selling live “green crabs”. The Seattle seller had bought the live green crabs from a seller in Massachusetts with the intention of selling them for crab stock and soup. The crabs were destroyed by WDFW Police officers.

The green crab, Carcinus maenas, is a widely distributed invasive species that eventually alters its new environment. It's assumed that such species have high genetic diversity, or a variety of characteristics allowing them to adapt and thrive. But the green crab has low genetic diversity, while still spreading rapidly in a new part of the world. A U.S. National Science Foundation-funded study led by Carolyn Tepolot of the Woods Hole Oceanographic Institution is investigating the adaptive mechanisms of the green crab along the west coast of North America, where it has shown extensive dispersal in the last decade despite minimal genetic diversity. The results are published in Molecular Ecology. The project is a collaboration among scientists at WHOI, Portland State University, the Smithsonian Environmental Research Center and the University of California, Davis.