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Crabs

More than 90 different kinds of crabs live in Texas coastal waters. They are found in every type of habitat from the saltiest water of the Gulf to the almost fresh water of the back bays. Crabs Their favorite habitat is mud bottoms where they can burrow to lie in wait for prey or hide from enemies.

Crabs are crustaceans with five pairs of legs. The first pair is modified as pinchers and the last four pairs are walking legs. Some have the last pair of legs modified into "paddles" so they can swim rapidly. Other common crustaceans are shrimps, lobsters, crayfish, and barnacles.

The Blue Crab

The blue crab (Callinectes sapidus), which favors brackish bays, is the most common edible crab along the East and Gulf coasts. It is also found on the East coast of South America and has been seen in the coastal waters of France, Holland, and Denmark.

Identification...

The back of the blue crab is dark or brownish green and is drawn out on each side into a large spine. When fully grown the spine may be more than 8 inches wide. The abdomen and lower legs are white. Crab claws are various shades of blue, but the claw tips of the female are red.

Sexes can be identified by the abdominal flap or apron. In the male it is shaped like an inverted T, but in the female it is broader.

Parasites are common on crabs. Barnacles, worms, and leeches attach themselves to the outer shell; small animals called isopods live in the gills or on the abdomen; and small worms live in the muscles. However, most of these parasites do not affect the life of the crab.

Molting...

As with other crustaceans, the blue crab must molt or shed its hard, outer shell as it increases in size. When the body becomes too large for its shell, a new soft shell is formed beneath the hard one. This stage is called "peeler." The "buster" stage begins when the hard shell splits, and the crab starts to back out. After freeing itself from the shell, the crab takes in large amounts of water and expands its soft and wrinkled body. During this soft stage the crab is easy prey and must seek shelter. The shell hardens in 2-3 days, and during this time it is called a "buckram" or "paper shell." Once the shell hardens, the crab resumes its search for food.

A crab may molt 20 times during its life and with each molting may increase its width 1/4 to 1/3 the previous size. Frequency of molting depends on the water temperature, food availability and the age of the crab.

Crabs can replace or regenerate pinchers or legs lost while fighting or protecting themselves. The lost limb will be replaced after two or more molts.

Mating...

Male and female crabs become sexually mature while living in the estuary. Maturity occurs around the age of 12 to 14 months, after 18 or more molts. The female mates only once after she has molted for the last time, but a male may mate often.

When the female is ready to mate, the male will carry the female beneath him by holding her with his first pair of legs. The pinchers are free to defend the pair, called "doublers," which may remain coupled for two days or more. After she sheds her shell, the male transfers the sperm to the female. When they are finished mating, the male holds the female until she develops a hard shell; then they go their separate ways. She carries the sperm internally until she is ready to spawn. Sperm from this mating will live up to a year and are sufficient to fertilize all the eggs produced in a female's lifetime.

After mating, the female migrates to the saltier portions of the lower bays and Gulf, while the male remains in the estuary. Spawning usually occurs within two to nine months of mating; with the exact time determined by the time of year. Most females spawn twice and then die. In Texas the spawning season lasts from December to October with a peak in spring and summer.

Spawning and Development...

When the female is ready to spawn, she fertilizes the eggs and places them on the hairs of the appendages on the abdomen beneath the apron. This egg mass takes up about 1/3 of her body and she is called a "sponge" or "berry" crab. An average egg mass contains about 1 1/2 to two million eggs and requires about 14 days to hatch. Of the millions of eggs spawned, few survive to become adults.

female or sponge crab with eggs

The age of eggs can be determined from this color code:

  • Orange-yellow -- 1st to 5th day
  • Brown -- 6th to 11th day
  • Black -- 12th to 14th day

The young, called larvae or "megalops," look very different from the adults. Larvae pass through eight stages in about two months before becoming crablike in appearance. Young crabs move toward areas of less salty water in the back bays, where they grow to maturity in about a year.

Crabs will eat almost any vegetable or animal matter. However, they prefer freshly dead or freshly caught food. Sometimes crabs will crush and eat young oysters or clams.

A string of crab traps at sunset

Economically...

The blue crab is the most important crab species in Texas. The crabs are sold live to processors (who boil, pick, and can the meat), to fish houses, and to supermarkets for sale over the counter. From 1977 to 1989, the yearly catch ranged between 6.9 and 11.7 million pounds, valued at $1,928,000 to $4,474,000. Generally, production has been highest in the bays that receive the most fresh water and lowest in those that receive the least.

Catching, Cleaning, and Eating...

Most of the crabs caught commercially are taken in crab traps. A trap is a rectangular device made of chicken wire about 2 feet wide. It has inverted funnels in the sides, through which the crab can enter, but will have difficulty leaving. The trap is baited with freshly dead fish. In some areas, crabs are also caught in trawls and by trotlines.

Commercial crab trap

In addition to the commercial fishery, many people crab for fun. It is inexpensive and easy for all members of the family. There are no bag limits, but there is a 5-inch minimum body width as measured from spine to spine. Keeping "sponge" crabs - female crabs with spongy masses of eggs on their abdomens - is also illegal.

One of the easiest ways to catch crabs is with fish heads or chicken necks tied to a piece of strong twine about 10 feet long or long enough to reach the bay bottom. Place the baited line in water from a pier, bank, or boat and wait until a crab grabs it. When there is a pull on the end, the string is slowly retrieved until the crab is seen. A net is used to dip it out, but the crab cannot be allowed to come out of the water because it will release the bait. Patience is the key!

Crabs should be cleaned quickly to prevent meat spoilage. Dead crabs should be discarded. Crabs can be boiled before or after cleaning. To clean the crab, remove the claws by holding the body in one hand and twisting the claw off with the other hand. Next, hold the legs in one hand, insert the fingers of the other hand under the shell at the back, and pull the shell up and off. Scoop out and discard the internal organs in the center of the crab. Slice the top of one side of the body with a knife and repeat on the other side. Now scoop out the meat from the exposed chambers. Refrigerate as soon as possible!

Blue crab meat is tasty and can be prepared in any number of ways. For recipes, write Texas A & M Extension Service, A & M University, College Station, Texas 77843.

Stone Crabs

Stone Crab

The stone crab has gained in popularity as a seafood delicacy in Texas and the commercial harvest has increased since 1984. This crab lives around rocky areas or oyster reefs and burrows into the sand. It is dark brownish-red with gray interspersed. Claws are hinged, very dark, and banded with red and yellow. All its legs are used for walking, and it has very strong pinchers used to crush oysters.

Stone crabs are fished near jetties, oyster reefs or other rocky areas just as for blue crabs. Stone crabs have small bodies and only the claws are eaten. To be kept, claws must be two and one-half inches long, measured from the tips of the immovable finger to the first joint. Only one legal size claw may be removed and then the crab must be returned immediately to the water. The claws are prepared in the same manner as blue crab claws.

Other Crabs

Most of the other crabs are either too small or too uncommon to be of economic value. Hermit crabs, ghost crabs, fiddler crabs, and the pygmy gulf crab are only a few of the common ones.

Once you start looking for crabs at the seashore and in the bays, you will be amazed at the many shapes and colors of their bodies and the unique places in which they live.

Adapted from "Crabs"
by Larry McEachron, Coastal Fisheries, TPWD, Rockport, Texas 78382




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