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The Snakehead Fish

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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.
Some via the live food fish trade by
individuals releasing these fish 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 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.
Suprabranchial Organ
S= The
suprabranchial organ
that the snakehead
fish uses to breathe
out of water with.
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.
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.
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
Perch
LargeMouth 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.
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.
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
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.
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 fouryear 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.
Some Snakehead Humor
http://www.youtube.com/watch?v=hIdPzM
1nOqA
(Night of the Snakehead)
http://www.youtube.com/watch?v=Epbafx
ClIS0
(Swarm of the Snakehead)
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