Monday, September 17, 2012

Tennessee's Most Unwanted

It’s been a long journey, but we are happy to report that two snakeheads are now in the new Invasive Species exhibit at the Tennessee Aquarium.  This tank calls attention to one of the most serious threats to our native animals: species that have been accidentally or purposefully released outside their native range.  As you study this tank full of “unwanted” animals, you will see the shells of Zebra Mussels (Dreissena polymorpha), and Asian Clams (Corbicula fluminea), in addition to Yellow Perch (Perca flavescens), Redbreast Sunfish (Lepomis auritus), Grass Carp (Ctenopharyngodon idella), and Northern Snakeheads (Chana argus).   Each of these species has an impact on the ecosystem it has been introduced into, some more drastic than others.

Zebra Mussels and Snakeheads have been two of the most expensive invasive species our country is battling.  Zebra mussels are native to Eurasia and were first found in the Great Lakes in the 1980s.  They were most likely introduced by ballast water from barges as they entered harbors and waterways.  Since then, Zebra Mussels have spread rapidly, densely colonizing virtually any surface, including other aquatic animals!  They outcompete native mussels for food and habitat, and millions of dollars are spent each year de-fouling industrial pipes clogged with zebra mussels.  
Zebra mussels growing on a crayfishFrom:

Pipe clogged with zebra mussels

Snakeheads are another invasive species that has gotten a lot of attention lately.  Due to their snake-like appearance, mouth full of sharp teeth, and ability to breathe air and “crawl” over land, the media has dubbed this animal “Frankenfish.”  While this name may be a bit harsh, there is no doubt that snakeheads have the potential to severely degrade an area where they are introduced.  They are voracious predators and highly territorial; therefore they can outcompete popular sportfish, like bass, for food.  They are also aggressive, especially during breeding season as they guard their eggs and larvae.  There are no established populations in Tennessee right now, though one snakehead was caught near Memphis in 2006.  There are established populations in Virginia, Florida, and Arkansas, however.  The largest eradication attempt in the U.S. was performed over 110 square miles in the Piney Creek drainage in Arkansas.  Biologists attempted to poison what they thought was a contained population.  This massive project was successful in diminishing the snakehead population, but was unsuccessful  in eradicating the river of them.   It is illegal to possess a snakehead in the state of Tennessee. 

Northern Snakehead at the Tennessee Aquarium
We are able to display these species thanks to funding from the Tennessee Wildlife Resources Agency.  Come visit the Aquarium to see our new exhibit in the Tennessee River Gallery of the River Journey building.  And remember--you can help prevent the spread of invasive species.  After being on the water, check your boat and equipment for aquatic hitchhikers, clean thoroughly after each use, and dry before use in a different waterbody.

1 comment:

alfred said...

Place the compression nut and compression ring over the end of the pipe, as shown above, then insert the pipe into the compression seat. Then using two wrenches, one to hold the fitting and the other for the compression nut, tighten the compression nut completely. This forces the compression ring unto the pipe, creating a water tight seal.

Fixing A Pipe