Blue Crabs

The blue crab (Callinectes Sapidus) is a 10-legged crustacean of the family Portunidae, which includes the swimming crabs. It is easily identified by its body color which is generally a bright blue along the frontal area, especially along the claws. The remainder of the body is shaded an olive brown color. As with other Portunids, the hind legs are adapted to a paddle-like shape to accommodate swimming. They are found in the waters of the western Atlantic Ocean and Gulf of Mexico ranging from Nova Scotia to Argentina. (They have also been successfully introduced into both Asia and Europe.) Being difficult to handle safely without proper equipment, they are capable of delivering a most painful pinch to the careless handler. They are noted for being particularly aggressive both in and out of the water. Blue crabs are also highly mobile, but are more active during daylight hours than in the evenings. They are able to move from 0-450 feet per hour, with an average of 50 ft. /hr. The total distance traversed per day for these crabs is approximately 700 ft.

The reproductive spawning of blue crabs varies by region. In Chesapeake Bay, for example, spawning is initiated in May and June, with a second spawning in August. In North and South Carolina, spawning occurs from March through October, with peaks from April to August. Around the Indian River Lagoon in Florida, spawning occurs from February to October, with peak spawning occurring from March through September. In the Gulf of Mexico, two spawning periods are common: one in February and March, and one in August and September. Unlike males, female blue crabs mate only one time in their lives, following their initial or pubertal molt. When approaching this molt, females release a pheromone in their urine which attracts males. Male crabs vie for females and will protect them until molting occurs. It is at this time that mating occurs. Mating may last as long as five to twelve hours. Blue crabs are extremely prolific, with females producing from two to eight million eggs per spawn. Eggs are brooded from fourteen to seventeen days, during which time females migrate to the mouths of estuaries so that larvae may be released into high salinity waters. Blue Crab larvae have a salinity requirement of at least 20 parts per thousand (ppt.), and show poor survival below this threshold.

Blue crabs are commercially harvested by using a trap known as a crab pot which is somewhat similar in design to northern lobster pots. Modern crab pots are generally made out of wire mesh, although older designs of wood and wire still exist, as well as all metal varieties and most all varieties are rectangular in shape. The crab pot usually contains two openings in the form of a tapered aperture that allow the crabs to squeeze in, allowing their entry but prohibiting their escape. A crab pot can be baited with almost any type of meat although fish is preferred. The bait is placed in a holding compartment, a separate meshed enclosure in the center of the pot which is accessible through a door on the bottom of the crab pot. This design attracts the crabs through the entrances while preventing them from completely removing the bait. The pots are distributed throughout the crabber's harvesting area in long straight lines and are checked every day or two for captures or depleted bait. Crabs that are caught are removed and then the pot is then re-baited and placed in the water for the next harvest.

The blue crab is a high value fishery species both within Florida and nationally. The statewide commercial catch of hard shelled Blue Crab between the years 1987 - 2001 was 217.3 million pounds, with a dollar value of over $142.5 million. Within the 5 county area encompassing the Indian River Lagoon (Volusia, Brevard, Indian River, St. Lucie and Martin Counties) the commercial catch of hard shelled Callinectes sapidus accounts for approximately 18% of the statewide total, with a harvest of 39.2 million pounds, and a value in excess of $25.1 million. This ranks the blue crab sixth in commercial value within the Indian River Lagoon, and second in pounds harvested.

 

© 2009-2012 Ozzie's Crabhouse LLC