Transcript The Snakehead Fish

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
Location of the Lung
S= The
suprabranchial organ
that the snakehead
fish uses to breathe
out of water with.
THIS FISH
BREATHES AIR !
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 24-48
hours.
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