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#1
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information on fish
Fish
[IMG]http://freshwatercichlids.info/wp-****************************/uploads/2009/02/fish-tuberculosis.jpg[/IMG] Fish are cold-blooded aquatic animals with backbones, gills, and fins. Most fishes are torpedo-shaped (fusiform) for efficient travel through water, but much variation occurs, from flattened and rounded, as in flounders, to vertical and angular, as in sea horses. Fishes range in size from the pygmy goby, Pandaka pygmaea, of the Philippines, which reaches only 12 mm (0.5 in) long and about 1.5 g (0.05 oz) in weight and is sexually mature at 6 mm (0.25 in), to the whale shark, Rhincodon typus, which grows to 18 m (60 ft) long and over 20 tons in weight. Fish were among the first animals systematically hunted by primitive humans. Even today, relatively primitive societies in the South Pacific and South America depend largely on fish for food; while in many industrialized nations, fish still constitute a major part of the diet. It is said that the search for codfish led French fishermen to the discovery of Canada and that villages sprang up on the coasts of Norway, Scotland, Japan, and other countries wherever shoals of herrings regularly came close to shore. Today fishes are harvested for unprocessed human food, fish meal, animal feed, and oil. They also are pursued avidly by sport anglers, who contribute to the economy of fishing areas and to specific industries. Currently, however, the increasing human population, overfishing to supply this population, and pollution of the world's waters are all cutting heavily into the world supply of fish, and threatening the existence of a number of species. At the same time, regulations to curtail the taking of certain species or sizes are virtually unenforceable on an international level. ![]() |
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#2 |
أكـاديـمـي فـعّـال
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the great white shark
![]() Great white sharks Kingdom Animalia Plylum Chordata SubPhylum Vertebrata Class Chrondrichthyes SubClass Elasmobranchii Order Lamniformes Family Lamnidae Genus Carchardon Species carcharias Marine life is rather intriguing considering the sizes, shapes and colors of the varied species of fish. Amongst all of them, one of the most dreaded is the entire range of shark species. They are dreaded because of their violent temperament. They do not appreciate human beings swimming into their domain. One species of the shark clan is the great white shark that swims around the coastal regions of the all the oceans. These sharks are also known as white pointer, white death, as well as white shark. The scientific name of this shark species is Carcharodon carcharias. The white sharks are the largest predatory fish in the world. It is the only species of the genus Carcharodon that has survived the ravages of time. The rest of the species have gone into extinction. The great white sharks are extremely sensitive to the electrical field emitted by the movement of living creatures. Their sensitivity is due to the extra sense that was given by the Ampullae of Lorenzini. The sharks are so sensitive that they can perceive half a billionth of a volt. These sharks primarily inhabit coastal regions where the water temperature ranges between 12 degrees C to 24 degrees C - 54 degrees F to 75 degrees F. However, they are found in large numbers around the southern coast of Australia, California, South Africa, Isla Guadalupe (Mexico). The maximum population inhabits the coastal region around the Dyer Island in South Africa. It was usually believed that the white sharks are not very social. However, recent researches have proven that this species is rather social. The sharks of South Africa apparently follow what is known as a dominance hierarchy based on size, genders and the rights of the squatters. The smaller sharks are dominated by the larger ones. The Newcomers are dominated by the resident sharks. They tend to resolve all their problems through the rituals they follow. The Great White is between 12-16 feet long, and can grow up to 19-21 feet. There is another main reason why the Great White is the most feared fish for humans. Great White Sharks are a very large species of shark. They are streamlined swimmers, and have a torpedo-shaped body with a pointed snout. They have about 3000 teeth, arranged in several rows. The first two rows of teeth are used for grabbing and cutting prey, while the teeth in the last rows rotate into place when front teeth are broken, worn down, or fall out. The teeth are triangularly shaped with serrations on the edges. The back of the shark is a dull grey color and the underside is coloured white. They have three main fins: the dorsal (on back) and two pectoral fins (on the sides). The tail is crescent shaped. There are five gill slits on Great White Sharks. The Great White reaches maturity about 9 years after it's birth. The growth of The Great White shark is about 25-30 cm per year. The White Shark has litters of about 7-9 pups. The females only reproduce twice in her whole life. Great White Sharks live in all coastal temperate waters, and have been known to occasionally make dives into the deep water of open oceans. They can be found in water as shallow as three feet deep, and as deep as 1280metres. They can be found on the following coastlines: California to Alaska, the east coast of the USA, most of the Gulf coast, Hawaii, most of South America, South Africa, Australia (except the north coast), New Zealand, Mediterranean Sea, West Africa to Scandinavia, Japan, and the eastern coastline of China to Russia |
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#3 |
أكـاديـمـي
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رد: information on fish
سبحان الله وبحمده
سبحان الله العظيم |
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مواقع النشر (المفضلة) |
الكلمات الدلالية (Tags) |
fish, information |
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الموضوع | كاتب الموضوع | المنتدى | مشاركات | آخر مشاركة |
اسئلة الانجليزي | طالبة كلية | منتدى كلية المجتمع بالأحساء | 1 | 2009- 2- 6 09:55 PM |