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Environmental Effects of Snakehead Species

In May, 2002, a local fisherman visited a government office in Annapolis , Maryland . With him, he had a photograph of a strange fish he had caught and re-released in Crofton. Before long, biologists had identified the fish as a Northern Snakehead.

The Northern Snakehead, Channa argus , is native to China and considered a delicacy in many South East Asian countries. They fish has developed in areas exposed to seasonal dry periods, where shallow waters risk becoming completely dried out. The Northern Channa is therefore able to travel over land by wriggling its body over the ground. A Northern Snakehead can breathe oxygen from the air and survive four days out of water. If it finds some mud to burrow it self in it can survive even longer periods of time. This has proved a very good survival strategy, since the Northern Snakehead can wriggle to a new home if its puddle turns dry, or burrow it self in the mud and wait for the next rain season

In China , the Northern Snakehead has its proper place in the eco-system, but on the American continents it can disrupt the native ecology. This can be especially harmful for already endangered fish species, since the Northern Snakehead is a skilled predator. About 90 percent of its diet consists of fish, but it gladly gulps down insects, crustaceans and plants as well. In China the Northern Snakehead lives in swamps, slow-moving streams and vegetated ponds – habitats that are easily found in many parts of America as well. Without any natural predators but with an abundance of suitable preys and habitats, the Northern Snakehead would most probably thrive in the U.S. It can survive in temperatures between 0 and 30 ° C / 32 and 86° F.

Despite its remarkable ability to travel, the Northern Snakehead has not wriggled its way into North America . Instead, it has most probably entered the waters when owners grew tired of caring for their pet fish. Northern Snakeheads are primarily sold as food on Asian markets in the U.S. , but they have also grown to be a quite popular. Their sturdiness and adaptability has given them a reputation as very easy to keep in fish tanks, and their aggressive temperament is also appreciated by many aquarists. Unfortunately, some pet owners set their Northern Snakehead free when they don't wish the care for them any more. Many Northern Snakeheads are suspected to have been released into the wild because their owners didn't want to feed the hungry fish any longer. A small Northern Snakehead can be bought for less than $ 7, but once it has grown to adult size the food can cost more than that – per day.

With this proved ability to consume large amounts of fish, anyone can understand that the catching of a wild Northern Snakehead in Maryland created some commotion when it occurred in May 2002. It also soon became clear that this was not the only Northern Snakehead living free in Maryland . In the Crofton pond where the first example had been caught, anglers and biologists caught one more adult Northern Snakehead in June and six young Northern Snakeheads in July. Some of the young Northern Snakeheads were no more than two inches (5 cm) long, which strongly suggested that they had been breed in the pond and not released from an aquarium. Apparently, the adult Northern Snakeheads in the pond had liked their new environment outside the fish tank so much that they had started to breed. By the end of July, more than 100 young Northern Snakeheads had been removed from the pond. Experts estimated their age to be around five months.

The discovery soon made it to the new papers. Many articles shared the biologists concern over the potential impact of the Northern Snakehead on the American eco-system. Other magazines opted for more catching head-lines about the Voracious Top-Predator Snakehead Fish that could breathe air and walk on land like Godzilla, the evil Chinese immigrant that wouldn't hesitate to sink its teeth into the Maryland inhabitants.

In August 2002, a two-step process aiming to eliminate the Northern Snakeheads from the Crofton pond was initiated. Stage one involved applying two different herbicides to the pond, causing a dramatic drop of the oxygen levels in the water. The next stage commenced two weeks later, when a piscicide was used to kill any remaining fish. Dead fish was removed from the Crofton pond every day and the whole area was vigilantly monitored. The water quality returned to normal after some weeks. Biologists were however concerned that the Northern Snakeheads might have escaped from the pond into the Little Patuxent River. The river is located no more than 75 feet (23 meters) from the Crofton pond and was consequently anxiously sampled, but no Northern Snakeheads were found.

In October 2002, Snakeheads were added by the U.S. Fish and Wildlife Service to the List of Injurious Wildlife Species. All 28 species of the Snakehead family were included, without any exceptions. By doing this, they effectively banned all importation into or transportation between the continental United States , the District of Columbia , Hawaii , the Commonwealth of Puerto Rico , or any territory or possession of the United States . Those who wish to import live Snakehead fishes or viable eggs today have to apply for a certain permit, and permits are only given for scientific, medical, educational, or zoological purposes. Federal agencies can still import without a permit, but only exclusively for their own use. If you already possess a living Snakehead or viable eggs inside the U.S. , any interstate transportation of them will also require a permit.

There is however reason to believe that the ban came too late. Since the first discovery in Maryland , reproducing populations of Snakeheads have been discovered in both Florida and California , and individual Snakeheads have been found in such diverse places as Massachusetts , Rhode Island , Maine and Hawaii . We know from experience what harm introduced species can do to an ecosystem. Once established, many species have proven more or less impossible to eradicate without causing even greater harm to the surrounding wild life. Examples of this include the introduction of the European Rabbit to Australia and the Kudzu plant to the U.S. Exotic species is not only dangerous to a few, already endangered native species. Since every eco-system is an extremely intricate web of factors, the adding of a new species can also mean that parasites and diseases suddenly start to thrive, or that the new species cause genetic pollution by interbreeding with existing species. It is hard to tell in advance what will happen. Sometimes one new species can turn out to be a true pest for the whole area, while one other equally non-native species blend into to the existing eco-system without causing any noticeable harm. We have to keep in mind that the Earth's environment is far from static and that plants and animal species always are striving to spread and find new grounds. This is a process that has been going on since life originated in the sea and without it the continents would never even have been inhabited by life forms. During the last centuries, however, human travelling have risen to levels never before experienced in the Earth's history and spreading processes that earlier might have taken several decades, centuries or even millennia, can today be achieved in no time. We therefore have to be very careful and watchful over the spreading of species into new areas by human hand.

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Environmental Effects of Channa Species