INVASIVE SPECIESINVASIVE SPECIESNorthern Snakehead FishNorthern Snakehead Fish

Some HistorySome History

Native to Africa and Native to Africa and Asia.Asia.

First discovered in First discovered in Maryland, USA in Maryland, USA in 2002.2002.

IntroductionIntroduction

Experts believe that the snakehead Experts believe that the snakehead entered U.S. waters by aquarium owners entered U.S. waters by aquarium owners releasing them.releasing them.

Some were released to support the live Some were released to support the live food fish trade and to establish a local food fish trade and to establish a local food source.food source.

Evolutionary Physical TraitsEvolutionary Physical TraitsThey can travel across land and live out of water for up They can travel across land and live out of water for up to three days as long as their body is wet. to three days as long as their body is wet.

Out of the water Snakeheads rhythmically move their Out of the water Snakeheads rhythmically move their fins and muscular bodies back and forth. The fish fins and muscular bodies back and forth. The fish equivalent of walking.equivalent of walking.

They need to breathe atmospheric air, if they They need to breathe atmospheric air, if they DO NOT DO NOT get this air they will get this air they will DIEDIE..

Snakeheads can breathe air unlike other fish as they use Snakeheads can breathe air unlike other fish as they use a primitive lung above their gills -air chambers. Which is a primitive lung above their gills -air chambers. Which is called a suprabranchial organ. called a suprabranchial organ.

Suprabranchial OrganSuprabranchial Organ

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

THIS FISH BREATHES THIS FISH BREATHES AIR !AIR !

Location of the LungLocation of the Lung

ReproductionReproductionScientists know little Scientists know little about the reproduction about the reproduction of snakeheads.of snakeheads.

These fishes probably These fishes probably have only one mate.have only one mate.

And they take care of And they take care of their eggs and young their eggs and young very carefully.very carefully.

Baby Snakehead Fish Baby Snakehead Fish Breathing Air out of WaterBreathing Air out of Water

Reproduction Cont’dReproduction Cont’dMany snakeheads clear plants & then build a simple circular Many snakeheads clear plants & then build a simple circular nest at the water surface.nest at the water surface.

The male encircles the female who lays thousands of eggs The male encircles the female who lays thousands of eggs which are then fertilized by the male.which are then fertilized by the male.

The eggs float upward into the nest which the parents guard.The eggs float upward into the nest which the parents guard.

After hatching, the young are still cared for by both parents.After hatching, the young are still cared for by both parents.

In two species the male keeps the fertilized eggs & later the In two species the male keeps the fertilized eggs & later the young in his mouth for a few days.young in his mouth for a few days.

Reproduction & NestingReproduction & Nesting

A mature northern A mature northern snakehead female can snakehead female can carry as many as 50,000 carry as many as 50,000 eggs.eggs.

Depending on water Depending on water temperature, eggs can temperature, eggs can hatch in about 24-48 hatch in about 24-48 hours.hours.

When the fry hatch, they When the fry hatch, they remain clustered at the remain clustered at the surface of the nest until surface of the nest until their fins develop.their fins develop.

BehaviorBehaviorSnakeheads are active during the day.Snakeheads are active during the day.

The hunt by ambush.The hunt by ambush.

Adults hunt alone, but young hunt in schools.Adults hunt alone, but young hunt in schools.

Sometimes snakeheads jump from water Sometimes snakeheads jump from water surface to grasp their prey.surface to grasp their prey.

Snakehead Fish vs. Native FishSnakehead Fish vs. Native FishSnakehead

Large Perch

Large Mouth Bass

Effects in US WatersEffects in US WatersDuring all life stages, snakeheads compete with native During all life stages, snakeheads compete with native species for food and habitat. species for food and habitat.

As juveniles, they eat zooplankton, insect larvae, small As juveniles, they eat zooplankton, insect larvae, small crustaceans, and the young of other fishes.crustaceans, and the young of other fishes.

As adults, they become voracious predators, feeding on As adults, they become voracious predators, feeding on other fishes, crustaceans, frogs, small reptiles, and other fishes, crustaceans, frogs, small reptiles, and sometimes birds and small mammals.sometimes birds and small mammals.

Should snakeheads become established in North Should snakeheads become established in North American ecosystems, their predatory behavior could American ecosystems, their predatory behavior could drastically disrupt food webs and ecological conditions, drastically disrupt food webs and ecological conditions, thus forever changing native aquatic systems by modifying thus forever changing native aquatic systems by modifying the array of native species. the array of native species.

Human EffectsHuman EffectsSnakehead’s can Snakehead’s can potentially transfer potentially transfer pathogens (harmful pathogens (harmful parasites and parasites and bacteria/viruses, to native bacteria/viruses, to native fishes.fishes.

Fishery scientists need to Fishery scientists need to study this potential to study this potential to determine if diseases and determine if diseases and parasites can be parasites can be transferred to North transferred to North American species. American species.

Humans are Helping the InvasionHumans are Helping the InvasionCurrently, snakeheads are being sold in live fish Currently, snakeheads are being sold in live fish food markets and some restaurants in Boston food markets and some restaurants in Boston and New York. and New York.

Live specimens have been confiscated by Live specimens have been confiscated by authorities in Alabama, California, Florida, authorities in Alabama, California, Florida, Kentucky, Texas and Washington. All states Kentucky, Texas and Washington. All states where possession of these fish is illegal.where possession of these fish is illegal.

Also, snakeheads are readily available for Also, snakeheads are readily available for purchase over the Internet.purchase over the Internet.

Geographical Range of SnakeheadGeographical Range of Snakehead

States that Declared Snakehead IllegalStates that Declared Snakehead Illegal