Crab Basics

Found in salt, fresh, and briny water, the crab hides under rocks, amid seaweed, and in crevices. Crabs are usually very aggres­sive and are skillful, combative predators that charge at their prey. If a crab’s leg becomes stuck or is restrained by an enemy, the crab simply detaches itself from the limb—any limbs lost in this way will grow back completely over the course of three moltings.

The crab has a rounded shell that can range from oval to heart-shaped, depending on the species. Its underdeveloped tail and abdomen are tucked under its shell, which can be either hard or soft, depending on how recently the crab has molted. The crab has protruding eyes and five pairs of limbs, the front pair of which develops into powerful pincers. The ventral fin of female crabs is much more highly developed than that of male crabs because it is used to hold the eggs. Although the crab is not a very fleshy animal, one quarter of its body is edible, including the flesh inside its body, legs, and pincers, as well as the liver and the creamy substance underneath the shell. The lean, white flesh is stringy and flavorful.

Of the approximately 4,000 different species that make up the crab family, the following are among the most common:

The Atlantic common crab inhabits rocky and sandy coasts and can dive to depths of more than 300 feet. Its smooth, oval reddish-brown shell is usually 4–8" wide but can grow to almost 16". Also known as the “edible crab,” it has very flavorful flesh.

The blue crab is very popular in the United States. Usually 6–8" wide, it thrives in Atlantic coastal waters from Delaware to Florida and is also known as the Atlantic blue crab. It represents approximately one half of the output of the American crab fishery and has been introduced into European waters. Its sweet flesh is excellent.

Also called the green crab, the common shore crab is the single most common species of crab. Frequently found on beaches, it is relentless in its pursuit of other crustaceans and mollusks and moves in a very peculiar fashion—a trait highlighted by its Latin name maenus, which means “frenzied.” The common shore crab weighs about 7 ounces and contains very little flesh; its small green shell is usually about 3" wide. Rarely sold commercially, it is sometimes used as bait by sports fishermen.

The Pacific common crab lives in cold waters and belongs to the same family of rock crabs as the Atlantic common crab. It can grow to be 9" wide and usually weighs 2–4 pounds. Its shell is a brownish color. Whole Pacific common crabs are sold live, cooked, canned, or frozen. The delicious flesh is also available fresh or frozen.

The spider crab lives on sandy seabeds at depths of up to 165 feet. It can be pink, pinkish yellow, or reddish brown and is typically 4–8" wide. Also known as the “spiny crab,” it has a rounded triangular spiny shell that is somewhat heart-shaped, and long, slender legs that are arranged like those of a spider. Its flesh is considered to be excellent, but the flesh of the female is more flavorful than that of the male.

The snow crab is a member of the spider crab family. Its shell is almost perfectly round but is slightly broader at the rear end. Its legs are long and somewhat flat. Often orangey-brown, its coloring varies depending on how recently the crab has molted. Only the male of the species is fished, since it is much larger than the female. It can be more than 5" wide and can weigh almost 3 pounds. The snow crab lives in cold water at depths ranging from 65–2,300 feet, which enhances the quality of its uniquely flavored, much-sought-after flesh.

North American fishermen long regarded the snow crab as a nuisance because it became entangled in their nets and had little commercial value. Initially marketed as “queen crab,” with very little success, it is now sold under the more attractive name “snow crab,” which originated in Asia. Now much sought after, the snow crab has even come to be regarded as a delicacy.

The velvet swimming crab measures 3–6" in diameter, and as its name suggests, its shell and legs are covered with velvety hair. It has powerful pincers and flat rear legs that resemble fins. Its reddish brown shell is adorned with blue spots. The flesh of the velvet swimming crab is highly prized.

The term soft-shell crab doesn't refer to a specific species of crab. Rather, it’s a name given to crabs that have recently molted. More precisely, soft-shell crabs have shed the shells they have outgrown and have yet to replace them. Though many species of crabs are eaten as soft-shell crabs, the only crab species commercially sold as soft-shell crabs are blue crabs. These crabs are usually caught between 6–48 hours after they begin to molt, which generally occurs between mid-May and mid-September. This short fishing season accounts for the rarity of soft-shell crabs, which many people regard as a delicacy. Soft-shell crabs are usually sold live but are generally in such a weakened state that they appear to be dead. Practically transparent, they are usually cleaned (the gills and the tail are removed, and the crab is then rinsed in cold water) and sautéed in butter, or fried and served with tartar sauce.