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SNAKEHEAD PDF, EPUB, EBOOK Anthony Horowitz | 388 pages | 04 Sep 2008 | Penguin Putnam Inc | 9780142412121 | English | New York, NY, United States Snakehead (fish) - Wikipedia They are all fierce and very capable predators, however, and they can all breathe in air. Snakeheads are native to Asia and Africa. They have been transported to North America for the pet trade and for food stores that sell living fish. The animals have appeared in some U. Their presence in the wild is very worrying. They have no natural predators in North America and may be a serious threat to native wildlife. Snakeheads have an elongated body. Different species exhibit different color patterns. Fin placement and appearance is the same in all of the species, however. It's one method used to identify invasive snakeheads in North America. The fish have a long dorsal fin on their back, as shown above. The pectoral fins are located on their sides behind their head. The pelvic fins are located on the undersurface almost directly below the pectoral fins. The anal fin is located on the undersurface towards the rear of the animal and is generally about two thirds of the length of the dorsal fin. Like other fish, snakeheads have a caudal tail fin at the end of their body. There are two genera of snakeheads. Member of the genus Channa live in Asia, Indonesia, and Malaysia. The genus Parachanna is found in Africa. The video below shows the peacock snakehead, or Channa pulcra. The head of a snakefish has enlarged scales. The eyes are often shifted towards the front of the head. These features resemble those of a snake, giving the fish their name. Snakeheads obtain oxygen from air as well as water. The animals use their gills to obtain oxygen from water, just as other fish do. Water enters their mouth and travels to the gills on both sides of the body. Oxygen passes from the water into the gill tissue and then enters blood vessels. The water leaves the gills through the opening behind the operculum the bony flap that covers each gill chamber. To breathe in air, the fish use a space in their head above their gills called the suprabranchial chamber or the suprabranchial organ. Air that the fish gulps from the water surface enters the suprabranchial chamber. Here oxygen from the air passes into blood vessels in the tissue lining the chamber. The suprabranchial chamber of a snakehead is quite similar to the labyrinth organ found in some other air-breathing fish. Examples of labyrinth fish include the Siamese fighting fish, the climbing perch, and many types of gouramis. George Chemilevsky, via Wikimedia Commons, public domain image. The giant snakehead C hanna micropeltes lives in freshwater, like other snakeheads. Living up to its name, it may reach more than 3. The fish is quite variable in appearance. It has a dark grey, blue-black, or black background color with white, silver, or blue-green markings. The undersurface of the fish is much lighter in color than the rest of the fish. The giant snakehead is also known as the red snakehead. This name comes from the color of the young fish, or fry. In some parts of the world, fisherman refer to the giant snakehead as a toman. It's a popular prey in sport fishing and is also enjoyed as an edible fish in some countries. The fish has a reputation as a fearsome and even vicious predator. Its diet consists mainly of other fish, but it also eats frogs, crustaceans, and even birds. It reportedly kills more animals than it eats. Giant snakeheads create a nest by clearing a cylindrical area in the middle of aquatic vegetation. When the eggs are laid, they rise to the top of the water column and are carefully guarded by the adults. The parents also guard the fry, which helps the youngsters to survive. A fry of the giant snakehead; the young fish is about two weeks old. Although they are classified in the same genus, the Northern Snakehead Channa argus and the giant snakehead look quite different from one another. The northern snakehead is an attractive animal that has a tan, brown, grey, or grey-green background color decorated with darker blotches and stripes. The body is torpedo-shaped, and the top of the head is noticeably flattened. The lower jaw of the fish protrudes beyond its upper jaw. The northern snakehead is native to China, Korea, and Russia and has spread to other areas of Southeast Asia. It lives in areas where the water is muddy and is flowing slowly or is stagnant. It feeds mainly on other fish but also eats crustaceans and insects. Like the giant snakehead, it's often described as "ferocious". The species is an obligate air breather—it must breathe air as well as absorb oxygen through its gills in order to survive. There is some debate about how capable the fish is at moving over land. There are claims that it can travel on land and survive for three or four days out of water, provided it stays moist, just like a giant snakehead. Many researchers say that it can't move far when it leaves the water and that under normal circumstances it can survive for only a few hours in air, however. There is still a lot to learn about the life history and reproduction of the northern snakehead. Understanding the fish's habits is essential in order to control its population when it becomes invasive. In , a northern snakehead nest was discovered in the Potomac River in the United States. The nest was a cylindrical column of water surrounded by an aquatic plant called Hydrilla. A circular mat of Hydrilla formed a canopy or roof on top of the nest. Orange-yellow eggs had been laid on the canopy. The eggs weren't adhesive and were held in place and hidden by the plant leaves and stems. The adults—both the male and the female—patrolled the water underneath the canopy. Northern snakehead nests have been found in other areas, too. They have all been cylindrical nests surrounded by vegetation and have been about one meter in diameter. These nests have lacked a canopy, however. The fish have a high fecundity and lay 22, to , eggs at a time. They breed up to five times a year. Although some of the eggs and fry die, parental care likely improves reproductive success compared to the situation in fish that don't guard their young. Wild snakeheads, including giant snakeheads, are sighted periodically in various parts of North America. In at least three areas, snakeheads have formed a resident population and are reproducing. The northern snakehead is found in the Potomac River and its tributaries in the state of Maryland. The bullseye snakehead Channa marulius has established itself in part of Florida. The adults of this species frequently have red eyes and a black spot surrounded by orange at the base of their tail fin. The blotched snakehead Channa maculata lives in Hawaii and is quite similar in appearance to the northern snakehead. Snakeheads are thought to have entered the wild when they were released from home aquariums, perhaps when they grew too large or too expensive to keep. They may also have been released into ponds by fish sellers or other people who hoped that the animals would reproduce to produce a convenient and free source of edible fish. The northern snakehead has established itself firmly in the Potomac River system, with a population estimated at somewhere above 21, individuals, ranging through more than river miles kilometers. I live in British Columbia. In , a snakehead fish was found living in a pond located in Central Park in Burnaby, BC, not far from my home. The fish is shown in the video below. It was caught when the pond was partially drained. There were concerns that the fish was a northern snakehead, which would have been capable of living through a southwestern BC winter. In November , however, the fish was identified as a blotched snakehead. This species would be unlikely to survive through the local winter, which although mild in terms of Canadian winters is much colder than the climate in the snakehead's native habitat. If the fish had survived and reproduced, native fish may have been eaten and their populations harmed. Researchers said that there was no evidence that the animal had reproduced, however. They also said that it likely survived by eating other non-native species placed in the pond, such as goldfish and fathead minnows. No more wild snakeheads have been discovered in the province since the discovery, to the relief of many British Columbians, including me. The presence of wild snakeheads in North America worries some conservation officers and officials very much. The fish have no natural predators. There is talk of horrible scenarios such as native animal species being wiped out by the fish. Snakeheads may not only prey on native animals but also pass parasites to them. The presence of any invasive species—especially a predator—must always be taken seriously. Snakeheads definitely have the potential to create an environmental problem. The areas that they have invaded need to be monitored closely. It may only be a matter of time before serious effects are noticed due to the presence of the fish. At the moment, though, it's not clear how much damage snakeheads are causing to their ecosystem and how significant or widespread any damage is. In Maryland, officials have enlisted the aid of the public in the effort to control the northern snakehead population.

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