INVASIVE SPECIES Northern Snakehead Fish

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

Introduction Experts believe that the snakehead entered U.S. waters by aquarium owners releasing them. Some were released to support the live food fish trade and to establish a local food source.

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 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.

Suprabranchial Organ S= The suprabranchial organ that the snakehead fish uses to breathe out of water with. THIS FISH BREATHES AIR ! Location of the Lung

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 very carefully. Baby Snakehead Fish Breathing Air out of Water

Reproduction Cont’d Many snakeheads clear plants & then build a simple circular nest at the water surface. The male encircles the female who lays thousands of eggs which are then fertilized by the male. The eggs float upward into the nest which the parents guard. After hatching, the young are still cared for by both parents. In two species the male keeps the fertilized eggs & later the young in his mouth for a few days.

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

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.

Snakehead Fish vs. Native Fish Snakehead Large Perch Large Mouth Bass

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.

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.

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.

Geographical Range of Snakehead

States that Declared Snakehead Illegal