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Northern Snakehead Fish ( Channa argus )

Northern Snakehead Fish ( Channa argus ) Some History Native to Africa and Asia. First discovered in Maryland in 2002. Introduction Experts believe that some entered U.S. waters via releases by aquarium owners.

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Northern Snakehead Fish ( Channa argus )

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  1. Northern Snakehead Fish(Channa argus)

  2. Some History Native to Africa and Asia. First discovered in Maryland in 2002.

  3. Introduction • Experts believe that some entered U.S. waters via releases by aquarium owners. • Some via the live food fish trade by individuals releasing these fish to establish a local food source.

  4. Evolutionary Physical Traits They can travel across land and live out of water for up to three days as long as their body is wet. Out of the water Snakeheads rhythmically move their fins and muscular bodies back and forth. The fish equivalent of walking. They have a physiological need to breathe atmospheric air, if they DO NOT get this air they will DIE. Snakeheads can breathe air unlike other fish as they use a primitive lung above their gills -air chambers. Which is called a suprabranchial organ.

  5. Suprabranchial Organ • S= The suprabranchial organ that the snakehead fish uses to breathe out of water with.

  6. Reproduction • Scientists know little about the reproduction of snakeheads. • These fishes probably have only one mate. • And they take care of their eggs and young.

  7. Reproduction Cont’d Many snakeheads clear plants & then build a simple circular nest at the water surface. The male encircles the female, squeezes out her eggs, & fertilizes, or placed sperm on, them. The eggs float upward into the nest, which the parents guard. After hatching, the young are cared for by either parent, depending on species. In two species the male keeps the fertilized eggs & later the young in his mouth for a few days.

  8. Reproduction & Nesting • A mature northern snakehead female can carry as many as 50,000 eggs. • Depending on water temperature, eggs can hatch in about 24-48 hours. • When the fry hatch, they remain clustered at the surface of the nest until their fins develop.

  9. Behavior Snakeheads are active during the day. The hunt by ambush. Adults hunt alone, but young hunt in schools. Sometimes snakeheads jump from water surface to grasp their prey.

  10. Snakehead Fish vs. Native Fish Snakehead Perch LargeMouth Bass

  11. Effects in US Waters During all life stages, snakeheads compete with native species for food and habitat. As juveniles, they eat zooplankton, insect larvae, small crustaceans, and the young of other fishes. As adults, they become voracious predators, feeding on other fishes, crustaceans, frogs, small reptiles, and sometimes birds and small mammals. Should snakeheads become established in North American ecosystems, their predatory behavior could drastically disrupt food webs and ecological conditions, thus forever changing native aquatic systems by modifying the array of native species.

  12. Excellent video Clip From Virginia Game & Inland Fisheries • Please view the link to the video produced by the Virginia Department Game and Inland Fisheries. The film is narrated by John Odenkirk. The link is located on our class webpage.

  13. Human Effects • Snakehead’s can potentially transfer pathogens (harmful parasites and bacteria/viruses, to native fishes. • Fishery scientists need to study this potential to determine if diseases and parasites can be transferred to North American species.

  14. Humans are Helping the Invasion • Currently, snakeheads are being sold in live fish food markets and some restaurants in Boston and New York. • Live specimens have been confiscated by authorities in Alabama, California, Florida, Kentucky, Texas and Washington. All states where possession of these fish is illegal. • Also, snakeheads are readily available for purchase over the Internet.

  15. Geographical Range of Snakehead

  16. States that Declared Snakehead Illegal

  17. What are the FWS Doing? • Under the authority of the Injurious Wildlife provisions of the Lacey Act, the Service is proposing to list the snakehead family as injurious. • This action would prohibit the importation and interstate transport of 28 snakehead species. • After conducting an exhaustive analysis of the best available information, the Service has deemed that this action is necessary to protect the interests of wildlife and wildlife resources from the purposeful or accidental introduction of snakehead species into the ecosystems of U.S.

  18. Negative Impacts of This Action • The best available data show that there is a tradeoff between damage avoided by not letting snakeheads into the U.S. and the economic benefits received by the specialized sectors that currently import these fish. • Data collected by the Service indicate that $85,000 worth of snakeheads were imported into the U.S. over a four-year period from 1997 to 2000. • The potential damage that could be done by snakeheads if they become established in U.S. waters would likely be in the millions of dollars and would appear to significantly outweigh the benefits generated by the current market.

  19. Some Snakehead Humor • http://www.youtube.com/watch?v=hIdPzM1nOqA (Night of the Snakehead) • http://www.youtube.com/watch?v=EpbafxClIS0 (Swarm of the Snakehead)

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