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Mid-Atlantic waters offer many types of fishing, but blue crab probably
receives the most attention. Whether on a yacht or dinghy, a pier or mud
bank, the sight of a string tied to a chicken neck or fish head is a common
sight in the coastal zone. Blue crabs are invertebrates belonging to the largest group, or phylum, of animals called Arthropoda, or joint-legged animals. More specifically, they are decapod crustaceans, meaning they are arthropods with 10 legs and a hard shell. Scientists know the blue crab as Callinectes sapidus, which is quite descriptive since Callinectes means beautiful swimmer and sapidus means savory. Blue crabs have a varied diet but are most often thought of as scavengers that feed on a variety of dead animals. Decaying animals produce odors that the crab detects and locates with its extremely sensitive antennae. Actually, blue crabs prefer live or fresh food over decaying matter. At night, they can be seen swimming around lighted piers preying on bait fish and smaller blue crabs. Crabs will also lie motionless on the bottom waiting for an unsuspecting passerby. Clam, oyster, and mussel beds are often feeding areas for blue crabs. Biologists have estimated that an adult blue crab may eat over 1,200 juvenile clams a day. Salt-marsh cord grass (Spartina), eelgrass (Zostera), sea lettuce (Ulva), and other plants are also part of the blue crab's diet. The blue crab is Delaware's most valuable fishery, with an average commercial catch of 50,000 bushels of hard shells and peelers per year. Two methods are most common in commercial crabbing: potting and dredging. Potting accounts for the majority of the catch and commercial licenses are issued based on the number of pots used. Dredging is a winter fishery from December 15-March 30 in Delaware. The crabs winter in beds in the Delaware Bay at depths of over 30 feet. Dredges are pulled through the beds, catching the wintering crabs. The vast majority are females and usually are sold to picking houses. Crabs are sold according to size and/or sex. Large male crabs 6 inches or more are called No. 1 Jimmies and command a premium price. No. 2 Jimmies are males 5 inches or more. Sooks, or mature females, are sometimes mixed with the No. 2s. Often No.2s and sooks go for the same price. However, price and size limits vary depending on supply and demand. Commerccial picking houses expect a 10-15% yield of meat from a crab. In the Delmarva area, the other 85-90% (shell, viscera, and unpicked meat) is ground and added to chicken feed. Sea Grant scientists at the University of Delaware and other institutions across the country are researching different ways to use shell waste. The shell contains a cellulose-like substance called chitin (pronounced "kite' n") that has shown potential for industrial use. Possible uses for chitin include biodegradable films for packaging, sausage casing, surgical sutures, and as a clarifying agent in distilling processes. CULINARY DESCRIPTION When you cook blue crabs, it is critical that the crab meat reach an internal temperature of 70 degrees C (158 degrees F) for at least one minute to insure the destruction of the bacteria Vibrio cholerae, which may contaminate blue crabs. For safety, steam the crabs for 25-30 minutes or boil them for approximately 15 minutes. Either method is effective. If you don't eat all the crabs you cook, by all means pick the meat and make crab cakes, crab imperial, or a crab souffle. There are numerous recipes that call for crab meat. And you may, of course, buy the crab meat already cooked and picked. It is typically sold in one-pound containers in three forms -- backfin, claw, and special. The special crab meat is the least expensive and is ideal for making crab cakes. |
