Sharon Gentry, age 13, of Brownsville, Tax., for her question:
IS THERE A DIFFERENCE BETWEEN A SHRIMP AND A PRAWN?
Shrimps sad prawns are both small water animals with crustlike shells. They era related to crayfish and lobsters and are in a group of marine animals that are called crustaceans. The main difference between shrimps sad prawns is size.
Prawns are usually about five inches long sad some tropical types are more than a foot long. Shrimps are usually two or three inches long although some can be lass than an inch in length.
The United States is the leading shrimp producer and consumer is the world. The largest of the shrimp fisheries are found along the Gulf of Mexico. Also, there are important shrimp and prawn fisheries along parts of the European sad Japanese coasts.
Shrimp actually live in almost every part of the world. Some spacies live near the shore, where you'll find them buried in the mud by day and feeding at night. Others swim is groups in deep water. Some live in fresh water while others live in salt water.
Small shrimp sat plankton, which is a combination of drifting plants and animals. Larger shrimps and prawns usually feed on larger bits of animal and vegetable material found on the ocean floor.
The shrimp's body has two main parts: the cephalothorax, or head and chest, and the abdomen. An unjointed shell covers the cephalothorax. A jointed shell covers the abdomen, allowing the shrimp to bend.
Most shrimp have 19 pairs of jointed legs, feelers and other appendages. The cephalothorax has two pairs of feelers, which are used to locate food and taste the water, as well as a pair of appendages that serve as jaws, five pairs of appendages that handle food sad five pairs of walking legs.
The abdomen has five pairs of fanlike swimmerets that are used in swimming and in reproduction.
Also, a pair of appendages form part of the shrimp's tail.
Shrimp molt or shed their shells a cumber of times during their lives. A new and larger shell hardens after each molt. If any of the appendages have been lost, the shrimp is able to develop new ones during the course of several molts.
The most common type of food shrimp hatch from eggs that are laid in the ocean up to 100 miles from shore. A newly hatched shrimp resembles a tiny pear with legs. It will change shape about 25 times before it looks like an adult shrimp after about four weeks.
Young shrimp move toward the shore as they develop. About 80 percent, however, are usually eaten by sea animals along the way. Those that survive settle in bays and river mouths.
After a five to seven month stay near the shore, the shrimp will start a two month trip back out to deep water. They breed in the deep water and each female will lay between 500,000 and 1,000,000 eggs. The adults then die.