Shrimps Essay ⋆ Environment Essay Examples ⋆ EssayEmpire

This Shrimps Essay example is published for educational and informational purposes only. If you need a custom essay or research paper on this topic, please use our writing services. EssayEmpire.com offers reliable custom essay writing services that can help you to receive high grades and impress your professors with the quality of each essay or research paper you hand in.

Shrimps are decapod crustaceans from the infraorder Caridea found around the world in fresh and salt water and in both shallow and deep waters. There are about 2,000 species of shrimps; they range in length from a fraction of an inch to up to eight inches. Most are about 1.5-3 inches long, with the larger species commonly known as prawns. They are closely related to crabs, crayfish, and lobstersthe main difference is that they have a semitransparent body, a flexible abdomen, and a fan-like tail allowing them to swim easily. They often eat small plants, animals, or even carrion. Female shrimps may lay anywhere between 1,500 and 14,000 eggs depending on species and conditions.

The various types of shrimps include the common European or sand shrimp (Crangon vulgaris and Crago septemspinosus) found in the North Atlantic; the Peneus setiferus found off the east coast of North America from Mexico as far north as North Carolina; the brown-grooved shrimp (Peneus aztecus); and the pink-grooved shrimp (Peneus duorarum). The edible shrimps in the West Indies are Xiphocaris, which live in fresh water, with those from the genus Macrobrachium often being found in rivers in tropical countries.

Shrimps form the food source for numerous creatures, with the smallest type of shrimp, often known as krill-of which there are 82 species-providing the major part of the diet for baleen whales (such as blue whales, southern right whales, or humpback whales), and also for seals, penguins, squid, and fish. Blue whales consume many tons of krill each week. Krill, which are between one and two centimeters long as adults, live in vast swarms of up to 35 pounds per cubic yard in some parts of the Antarctic Ocean. It is not unknown for there to be tens of millions of krill in a single swarm, and this is what often attracts whales and other animals. Krill, which can often swim a few centimeters per second, can molt, leaving behind some of their skin, or exuvia, as a decoy for predators.

There is commercial fishing of krill in the Southern Ocean and the waters around Japan-krill is consumed by people in both Japan and Russia. However, its major use is as aquaculture feed, fish bait, and food for livestock and pets. To satisfy demand for these uses, there has been a recent increase in fishing fleets specifically designed to fish and process krill. This started in the Soviet Union during the 1960s, followed by Japan in 1972, and later by Poland, Chile, and South Korea. Ukraine also established its own krill fleet in 1991, and Japan, Poland, and the Ukraine are now the largest krill-fishing nations in the world.

The increase in whaling in the 19th century and for much of the 20th century allowed the krill population to increase. However, even with a much reduced whale population today, scientists have noticed a decline in krill numbers that they suspect is connected to the warming of the oceans from the greenhouse effect. If the cause of this is correct, this would affect the ecoenvironment of the oceans, as krill are an important part of the marine food chain. Krill may also have been affected by events such as the coccolithophore bloom in the Bering Sea in 1998, which resulted in a decline of diatoms, on which coccolithophores and krill both feed. Without the ability to feed on small coccolithophores, the population of krill off the coasts of western Alaska fell drastically with the result that there was a fall in other forms of fauna, particularly salmon.

Prawns have long been a part of human diets around the world, with shrimps being high in calcium and protein but low in food energy. Many seafood dishes incorporate prawns, with fried shrimp being a popular part of Asian and North American cuisine. Shrimps are also used in paella in Spain, and in many other Mediterranean and Portuguese dishes.

Originally all prawns were caught at sea. Shrimp fishing was particularly hazardous because of the weight of the nets, and the fact that some prawns tend to swim in rainstorms, making the hauling of nets dangerous. Gradually, as demand grew, shrimp fisheries were established. The first of these were small-scale concerns in Japan and southeast Asia; the kuruma shrimp was cultivated in shrimp farms starting in the 1930s. In the 1960s, large shrimp farms were established throughout Japan, and in the 1980s, in Taiwan, although the industry there had problems with diseases and management. In 1985, shrimp farms were built in Thailand to meet increased worldwide demand for shrimp-flavored sauces. A small shrimp farm was built in Brazil in 1974, and in Ecuador in 1978, but major production in Latin American only started in the 1990s; Brazil now has one of the major shrimp farming industries in the world. Many commercial hatcheries are still known as Galveston hatcheries because they were first developed in Galveston, Texas.

Bibliography:

Dorothy Bliss, Shrimps, Lobsters, and Crabs (Columbia University Press, 1982);
Everson, , Krill: Biology, Ecology and Fisheries (Blackwell Science, 2000);
L. Grey, A Guide to the American Penaeid Prawns (Department of the Northern Territory, 1983);
Smaldon, British Coastal Shrimps and Prawns (Linnean Society, 1979).