Invasive Species We Study: Green Crab

European green crabs are one of the most widespread invasive marine species on the planet. Where they are abundant, green crabs outcompete other native shellfish. They are voracious eaters and a major predator of clams, mussels, and oysters. They also actively disturb bed sediments, leading to the loss of the eelgrass that serves as essential habitat for Dungeness crab and Pacific salmon.

USGS is working to increase the effectiveness of Washington’s green crab early detection and rapid response program. Research at the USGS Western Fisheries Research Center aims to improve native shellfish habitat and limit the spread of European green crabs in coastal waters. Scientists have added new molecular technologies to the current monitoring program to broaden its capabilities. New research also looks at the compounding effects of climate change on the green crab populations (e.g., warmer waters = more green crabs). Ultimately, this work will help collaborators better control the spread of green crab and protect our region’s vital ecosystem, culture, and fisheries economy.