European Green Crab

Overview

The European Green Crab is a highly adaptable and widely distributed crustacean known for its aggressive nature and status as a successful invasive species. Originally native to the northeastern Atlantic and Baltic Sea, it has established populations in coastal ecosystems across the globe, often significantly impacting local biodiversity and fisheries.

Appearance

This medium-sized crab is characterized by a broad, triangular carapace that can reach up to 9–10 cm in width. A key identifying feature is the serrated front edge of the shell, which features five distinct spines on either side of the eyes and three rounded lobes between them. While commonly called "green," their coloration is highly variable, ranging from dark green and brown to mottled patterns, with undersides that may appear yellow, orange, or red depending on the individual's age and molting cycle.

Distribution & habitat

While native to the coasts of Europe and North Africa, the species is now found in many temperate regions, including the Atlantic and Pacific coasts of North America, South Africa, Australia, and parts of South America. They are predominantly found in shallow coastal waters, including estuaries, salt marshes, and intertidal zones, where they demonstrate a high tolerance for varying salinity levels and temperatures.

Biology & behavior

European Green Crabs are vigorous, generalist predators that can survive out of water for extended periods. They are known to be fierce competitors, often altering the behavior and population structure of native species in the areas they invade. They typically reach sexual maturity within their first year and are highly fecund, allowing them to rapidly colonize new environments.