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The nemertean worm Carcinonemertes carcinophila commonly parasitizes C. sapidus, especially females and older crabs, although it has little adverse effect on the crab. They include a number of viruses, bacteria, microsporidians, ciliates, and others. Callinectes sapidus is subject to a number of diseases and parasites. maenas is not found in the Chesapeake Bay, where C. sapidus is most frequent. C. sapidus may be able to control populations of the invasive green crab, Carcinus maenas numbers of the two species are negatively correlated, and C. C. sapidus typically consumes thin-shelled bivalves, annelids, small fish, plants and nearly any other item it can find, including carrion, other C. sapidus individuals, and animal waste. C. sapidus is an omnivore, eating both plants and animals. The natural predators of C. sapidus include eels, drum, striped bass, spot, trout, some sharks, humans, and cownose sting rays. In some parts of its introduced range, C. sapidus has become the subject of crab fishery, including in Greece, where the local population may be decreasing as a result of overfishing. The first record from European waters was made in 1901 at Rochefort, France. It has been introduced (via ballast water) to Japanese and European waters, and has been observed in the Baltic, North, Mediterranean and Black Seas. Distribution Callinectes sapidus is native to the western edge of the Atlantic Ocean from Nova Scotia to Argentina and around the entire coast of the Gulf of Mexico. When the crab is cooked, the alpha-crustacyanin breaks down, leaving only the astaxanthin, which turns the crab to a red-orange or a hot pink color. The blue hue stems from a number of pigments in the shell, including alpha-crustacyanin, which interacts with a red pigment, astaxanthin, to form a greenish-blue coloration. A female's abdomen changes as it matures: an immature female has a triangular-shaped abdomen, whereas a mature female's is rounded. It is long and slender in males, but wide and rounded in mature females one popular mnemonic is that the male's is shaped like the Washington Monument, while the female's resembles the dome of the United States Capitol. Males and females of C. sapidus can be distinguished by the sexual dimorphism in the shape of the abdomen (known as the "apron"). It can be distinguished from a related species occurring in the same area by the number of frontal teeth on the carapace C. sapidus has four, while C. Callinectes sapidus may grow to a carapace width of 230 mm (9.1 in). Males have a narrow abdomen, like the Washington Monument.