Blue Swimming Crab
Callinectes sapidus
Carapace width to 20cm

Four spines between eyes (cf the similar Ornate Swimming Crab - Callinectes ornatus - which has 6). Carapace wider than long, with lateral spines and  a long spike at widest point on each side.Green to brown with some
blue on claws and walking legs. The crab's blue hue stems from a number of pigments in the shell, including crustacyanin (blue), which is bound to a red pigment (astaxanthin) to form a greenish-blue coloration (on exposure to high temperatures  [cooking/ ecdysed exuviae on beaches etc]  these compounds disassociate, leading to exposure of the red pigment. Claws of equal size. Females have orange claws, males blue. Like all swimming crabs, the terminal segments of the rear waking legs are flattened to facilitate sculling.
Very aggressive crab, which can reach almost any point around body with its claws (beware!).

Live on sandy/ muddy bottoms from low tide mark to 120 ft/ 35m. Omnivorous, typically thin-shelled bivalves, annelids, small fish, plants and carrion.

Life Cycle:
Eggs of C. sapidus hatch in high salinity waters of inlets and coastal waters and are carried to the ocean by ebb tides. During seven planktonic (zoeal) stages blue crab larvae float near the surface and feed on microorganisms they encounter. After the eighth zoeal stage, larvae molt into megalopae. This larval form has small claws called chelipeds for grasping prey items. Megalopae selectively migrate upward in the water column as tides travel landward, eventually settling in shallow coastal waters.
Females typically exhibit 18 molts after the larval stages, while postlarval males molt about 20 times.
Blue swimming crabs typically reach maturity within one year  to 18 months.
    Ecological Descriptors
Habitat Size (cm) Diet Behaviour Sex 
S, M 20
Omn I F
Blue Swimming Crab Male
Blue Swimming Crab Male
Blue Swimming Crab Male
Blue Swimming Crab