The blue crab has become synonymous with the state of Maryland. Although, blue crabs can be found just about anywhere along the Atlantic seaboard, ranging from Maine to southern parts of South America. Affectionately called the “blue claw” but technically called “Callinectes sapidus”, this species of crab frequents the muddy shores of the Chesapeake Bay. And, Maryland natives are very familiar with how this greenish blue crustacean tastes when steamed and covered in Old Bay.
So let’s learn a little more about this underwater creature. I was a bit surprised, this last summer when a few friends were unfamiliar with the male and female differences with respect to blue crabs. I assumed that this was due to the fact that Maryland folks usually eat male crabs and don’t often see the female version. In terms of their outward appearance, the most obvious difference is the “apron” or the lower half of the crab. However it is less frequently noticed that the females have a red tips on their claws.
The blue crab’s shell is greenish blue on top and dingy white on the bottom. An adult crab measures about 5 to 9 inches long and 3 to 5 inches wide; the crabs’ legs are bluish in color. The blue crab has a distinctive, long sharp spine on each side, which it uses for protection. A series of shorter spines surround the front edge of the crab between the large spine and the eyes. A healthy crab has ten legs and sports some nasty pincers on its front two legs, called claws. The back set of legs are flat and designed for swimming.
Blue crabs are scavengers, they feed mostly on dead fish and plants, but might also feed on other crustaceans, worms and mollusks called bivalves. Anyone who has tried to catch a blue crab, knows that a tasty fish head, chicken neck or other unwanted poultry part will attract crabs like a magnet.
Blue crabs go through several stages of growth and get larger by shedding their shell called an exoskeleton. This process is called molting. When the crab molts, it exposes a new soft shell which hardens over time. Crabs may go through this process 15 to 25 times during a lifetime and this number varies between male and female crabs.
A blue crab will take from one year to eighteen months to fully mature, depending on several factors. Crabs in the warmer waters of the Gulf of Mexico, as an example, mature more quickly, while Chesapeake Bay crabs take longer to mature. The fact that Gulf of Mexico blue crabs mature faster, allows for year round harvesting. While the Chesapeake crabbing season is restricted to the spring, summer and fall months to allow for growth during colder months.