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THE SNAKEHEAD FISH
Transcript of THE SNAKEHEAD FISH
AP Environmental Science
Origins and evolution
Introduction into Florida
Research and collection methods
Snakeheads have long dorsal fins
Breathe air through gills
Their bodies are long and have a similar shape to snakes.
They have large mouths full of sharp, shiny teeth.
Their size and color depend on what species they are.
Snakehead fish are originally from China, Russia, and Korea.
First discovered in the USA in 1977 in California.
They were sold in pet stores and live fish markets. They were also popular in Asian food markets.
Snakehead fish are invasive species.
They adapt to any ecosystem.
Found in rivers in California, to Central Park in New York City, to swamps in Florida.
Origins and Evolutionary History of the Snakehead Fish
Many fossil records of the snakehead fish have been found all around the world, since they adapt to essentially any ecosystem.
Likely originated in India and Pakistan 50 million years ago.
They have two known ancestors: the
Their ancestors were also very adaptable to different ecosystems.
It is believed that their gills developed further because of droughts, so they could breathe air.
Their ability to walk out of water also developed due to droughts.
Fig.1- Distribution of Snakehead fish in the United States
Introduction to Florida
Snakehead fish used to be sold as pets. They have spread out all across the United States, including Florida because people no longer wanted to feed them.
A $7.00 snakehead fish can eat up to $8.00 in goldfish a day. These fish are constantly eating.
Snakehead fish are invasive species that have drastically changed Florida food chains and food webs.
They are considered invasive because they are carnivorous, predatory fish that have no natural predators.
They can also affect land food chains and food webs since they can "walk" on land and eat small mammals.
Snakeheads are super adaptable to any habitat. They have been seen from California, to Mississippi, to New York, to Florida.
They usually seek aquatic habitats where the water temperature is from 0 to 33 degrees Celsius.
Even though they prefer cooler temperatures, they still survive in warmer climates like Florida.
The snakehead's aggressive nature is what has allowed it to survive and migrate around the world.
They are solitary fish, meaning they only come into contact with other snakehead fish for reproductive purposes.
They impact every ecosystem they inhabit because they take out all native fish since they have no competition.
Stages of Development
Snakehead fish are born from eggs that the female protects.
Early juveniles remain in the "nest" for 3-4 weeks guarded by one parent or sometimes even both.
Snakehead fish eat any kind of fish,zooplankton, and may eat birds or small ducks, or even small mammals like squirrels, rats, rabbits.
They are considered piscivorous.
Hunting: They do not have a hunting pattern, they just eat what they find.
Reach sexual maturity at 2 years.
Females lay up to 50,000 unfertilized eggs.
Nests are about 2-3 feet deep with a diameter of 3 feet.
Few snakehead fish do not build nests, but carry the eggs in their mouths.
Female and male snakehead fish do not usually come in contact except for reproduction.
In some occasions, the male snakehead fish will stay with the female to guard the eggs and young fish.
One of the only fish species that guard their eggs and young for 3-4 weeks.
This photo shows a snakehead fish guarding it's young.
The size and pattern of snakehead fish depends on the species.
Most snakehead range from 12 to 35 inches.
There are smaller snakehead fish and larger ones as well.
The largest snakhead fish found was 6 feet long.
There are about 35 snakehead species.
It is unclear how many snakehead fish there are in the United States and much less the world.
They are considered invasive and illegal.
It is advised that if caught, they must be killed.
The result of snakehead fish invading ecosystems is an extinction of all native species.
By affecting the aquatic ecosystems, a ripple effect will be seen on the entire ecosystem itself.
They are difficult to kill.
The Snakehead fish has become so famous and such an envirnmental concern that even Disney created a comic about its effects and reputation.
Research and Collection Methods
There are no efforts in place to capture/collect or even tag/track snakehead fish. The goal is to kill them.
The control methods for this invasive species are limited because they are so aggressive and reproduce at a rapid rate.
The methods vary on where they are trying to be caught/killed.
Removal of the snakehead using traps, or even introducing predators that would eat the snakehead fish has not been successful.
Draining the water all together might work, but that would eliminate all native fish and also if any snakehead fish was even the slightest bit wet it would survive.
Fig.3 Electrofishing of snakehead fish
The best control method for eliminating snakehead fish is electrofishing. The problem is that it is dangerous, and it not only wipes out snakehead fish, but all other fish.
Table 1. US Importations of live Snakeheads (all species) 1997-2002
The future for the Snakehead fish is unclear. Based on this data,it is evident how snakehead fish became such a prominent threat to ecosystems in the United States and how difficult it would be to eliminate Snakehead fish.
I selected the Snakehead Fish for my Biodiversity project because when I was doing my Ocala National Forest project, I found information on how the snakehead fish was affecting Florida swamps, rivers, and lakes. I wanted to know more about this invasive species, so this was the perfect opportunity.
Photo 1-Unknown Author < http://snakehead_fish.tripod.com/ >
Photo 2-Unknown Author < http://dnr.wi.gov/topic/fishing/species/snakehead.html >
Photo 3-James F. Thompson < http://www.mediabistro.com/prnewser/why-the-snakehead-fish-needs-a-good-publicist_b64818 >
Photo 4-Unknown Author < http://ookaboo.com/o/pictures/source/91136/Ianare >
Figure 1-USGS-C Michael Hogan < http://www.eoearth.org/view/article/174540/ >
Figure 2-Walt Disney < http://www.monsterfishkeepers.com/forums/showthread.php?15343-Snakehead-Cartoon >
Figure 3-Washington Post-Urban Jungle-Unknown Author < http://www.washingtonpost.com/wp-srv/special/metro/urban-jungle/pages/130430.html >
Table 1-USGS < http://fl.biology.usgs.gov/Snakehead_circ_1251/html/us_importations.html >
Video 1-National Geographic < >
"Invasion of the Snakeheads!" by National Geographic