Mediterranean Green Crab

Overview

The Mediterranean Green Crab is a common littoral crustacean native to the Mediterranean, Black, and Azov Seas. It is a highly adaptable species frequently found in sheltered coastal environments, including lagoons and estuaries, where it plays a significant role in local ecosystems.

Distribution & habitat

This species is primarily found along the coasts of the Mediterranean and Black Seas, with populations also present in the Atlantic near the Canary Islands. It thrives in sheltered, shallow waters such as coastal lagoons, muddy sands, and areas with varying salinity. While it is a benthic species, it may migrate offshore during colder months.

Appearance

The carapace is roughly trapezoidal and typically mottled green or brown, though colors can vary. It is distinguished from its Atlantic relative, Carcinus maenas, by a shorter, toothed front edge between the eyes and straight, parallel male gonopods. The crab features five sharp lateral spines on each side of the carapace and robust, slightly unequal claws. Adults generally reach a width of 4 to 6 cm, with some individuals growing up to 8–10 cm.

Biology & behavior

As a generalist predator, it feeds on a diverse range of organisms, including molluscs, polychaetes, algae, and other benthic life. It is highly tolerant of fluctuations in temperature and salinity. The species exhibits sexual dimorphism, with males typically growing larger and possessing more robust claws than females. Like other crustaceans, it can regenerate lost limbs during the moulting process.

Reproduction

Breeding often occurs between late autumn and spring. Fertilized females typically move toward more marine environments to release their eggs. The larvae undergo a planktonic stage before settling into their benthic form.