The European green crab, Carcinus maenas, an invasives species, has been pre-sent in Casco Bay for over 100 years (League-Pike and Shulman 2009). However, green crab populations have recently grown dramatically along Maine’s coast, resulting in serious impacts to marine ecosystems and coastal fisheries. Green crabs are voracious predators and consume a variety of marine species, including soft-shell clams, eels, scallops and blue mussels, posing a significant threat to these commercial fisheries. Officials estimate that green crabs are the most significant threat in decades to Maine’s $15.6 million soft-shell clam industry. Even Maine’s lobster fishery may be affected. Young lobsters have been found in the stomachs of green crabs and studies have shown that green crabs can out-compete lobsters for food (Williams et al. 2009).
Casco Bay Estuary Partnership. (2013). European Green Crab (Fact Sheet). Portland, ME: University of Southern Maine, Muskie School of Public Service, Casco Bay Estuary Partnership.