Snakeheads in the USA

Snakehead fish became famous when wild and breeding specimens of this Asian predator was found in the United States. The fact that the Snakehead fish can grow larger than one metre and is highly adapted to low-oxygen waters and seasonal droughts naturally made the newspapers print article after article about this huge vicious predator fish that can breathe oxygen from the air and travel vast distances on land. The Snakehead is however not a ferocious baby-eater or pet dog attacker. There is a more sensible reason behind the Snakehead bans that were eventually issued by many of the US states. Since the Snakehead is a very capable predator that is not native to the US fauna, it might severely disrupt the ecosystem in regions where it is introduced. It can for instance compete with American predators for food or pose a treat to already endangered species that it perceives as prey.

Snakeheads are also known as Channa fish since they belong to the family Channa. The family Channa contains a wide range of different Snakehead species, eg Channa nox (Night Snakehead), Channa asiatica (Chinese Snakehead) and Channa amphibeus (Chel Snakehead). Their native habitats are found in Asia and Africa. Another name for Snakehead fish is Frankenfish. It is possible to keep Snakeheads in aquariums, but you should always find out how large the Snakehead species that you are interested in will grow before you buy it. Snakeheads grow very fast and some species will grow larger than one meter, which makes them unsuitable for most hobbyist aquariums. It is believed that the wild and breeding Snakeheads that were found in the United States originated from Snakeheads that had been released by their owners when the Snakeheads grew to large for their aquarium or when they required more food than the aquarists was willing to pay for. In Asia, the Snakehead is a very popular food fish and another rumor tells the story about the Asian immigrant that imported a Snakehead to the United States to prepare a traditional Asian remedy for his sick sister. The sister did however recover before the fish reached him, and he deicide to spare its life and release it into the wild.

The Snakehead craze began in 2002 when a fisherman caught a Snakehead in Crofton. He practiced catch and release, but since he did not recognize the fish he had caught he photographed it before he put it back into the water. He brought the photo to a government office in Annapolis, Maryland where it was identified as a Northern Snakehead – Channa argus. The Crofton pond was examined and it did not take long before another adult Snakehead was found. One moth later, six immature Channa argus was discovered in the same pond, which proved that the Snakeheads liked the Maryland environment well enough not only to survive, but to form breathing populations as well. Biologists determined that it was very unlikely that the immature Snakeheads were aquarium breed, since they were no larger than 5 centimeters (2 inches). During July 2002, more than 100 small and immature Snakeheads were removed from the Crofton pond.

The Maryland authorities launched a two-step process that they hoped would eradicate the Snakeheads from the Maryland fauna. Two potent herbicides were introduced to the Crofton pond, and the decaying plant material soon caused the oxygen levels to drop significantly. During the second part of the eradication process, piscicide aiming directly at the fish were used and large amounts of dead fish were removed from the waters. Since Snakeheads can breathe oxygen from the air and wiggle their way over land, the whole region around the Crofton pond was observed but not escaping Snakeheads were spotted. Biologists were afraid that Snakeheads would manage to escape to a nearby river – the Little Patuxent River that is located only 23 meters (75 feet) from the Crofton pond. The Little Patuxent River was explored, but no Snakeheads were found. After a few weeks, the water quality in the Crofton pond returned to normal.

Since this first discovery in Maryland, more Snakeheads have however been found in several American states. In Asia, Snakeheads inhabit quagmires, slow moving waters and densely grown puddles and ponds where they feed chiefly on fish, crustaceans and insects. Similar habitats with suitable prey exist in many parts of the United States, and the Snakehead could therefore become a permanent part of the fauna and cause severe disruption or the ecosystems. Wild Snakeheads have already been found in California, Florida, Rhode Island, Massachusetts, Maine and Hawaii. In Florida and California, the populations were established and breeding.