European Green Crab (Carcinus maenas)

A photo of a solitary European green crab on a sandy substrate.
(Filip Nuyttens, World Register of Marine Species)

The European green crab (Carcinus maenas) has spread far beyond its native continent, to waters off North and South America, Asia and Australia. It's a voracious eater and poses a nuisance to shellfish farmers. Invasive species have various means of reaching new habitats. Read about the role ships play in spreading invasive species.