Thursday, April 5, 2007
The Blue Crab
Despite its fearsome appearance and aggressive nature, the blue crab is greatly cherished in the South Carolina lowcountry. Many gourmets prefer the blue crab's sweet meat over all other locally-caught seafood. This interesting animal is often sought by recreational fishermen and it also supports a considerable commercial fishery.
The blue crab requires both inshore brackish waters and high salinity ocean waters to complete its life cycle. They are common from Massachusetts to Texas and a few have been reported as far north as Nova Scotia and as far south as Uruguay. The Chesapeake Bay, North Carolina and Louisiana support the largest blue crab fisheries.
Although other small swimming crabs in this family (Portunidae) occur locally, only the blue crab is of any commercial or recreational importance in South Carolina. The blue crab's scientific name, Callinectes sapidus, translates to "savory beautiful swimmer."
Swimming is accomplished by skulling the oar-like fifth pair of legs, the swimming legs. These paddles usually rotate at 20 to 40 revolutions per minute, but they quickly disappear into a blur as the animal darts away.
Walking is accomplished with the three pair of thin walking legs. Blue crabs almost always walk sideways clearing a path with their sharp lateral spines. The blue crab's most prominent features are the large and powerful claws which are used for food gathering, defense, digging and sexual displays. If not handled properly, blue crabs can inflict severe injury. Male crabs can be distinguished from females by the shape of the abdomen. The male has a T-shaped abdomen which is held tightly against the body until maturity when it becomes somewhat free. The immature female has a triangle-shaped abdomen which is tightly sealed against the body. The mature female's abdomen becomes rounded and can be easily pulled away from the body after the final molt.
Large males, often called "Jimmies" by fishermen, usually have brilliant blue claws and legs. The mature females or "sooks" can be distinguished by the bright orange tips on their claws. Males typically grow larger than females, sometimes reaching seven or eight inches in point-to-point width. Some males have been reported to grow to about ten inches.