NANFA-- USGS Warning on Exotics

Christopher Scharpf (
Sun, 18 Feb 2001 10:48:41 -0400

On 29 January, the U.S. Geological Survey (USGS) issued a public warning against
releasing aquarium fish into public waterways. Dumping of plants and
animals from aquariums is one of the major sources of invasive aquatic
species invasions, along with the discharge of ship's ballast water and
the escape of farmed fish from aquaculture operations. "Each year, more
than 2000 non-native fish species, representing nearly 150 million exotic
freshwater and marine fishes, are imported into the United States for use
in the aquarium trade," said a USGS spokesman. "Dumping them into
the nearest body of water when they are no longer wanted creates a
problem for the native fish species and for ecosystems in general."

If exotic fish survive and reproduce, they are difficult, if not
impossible, to control or eradicate. Their presence may lead to changes
in the native, or local, fish populations in an area through competition
with native species or by preying on them. Aquarium fish that are
dumped into the nearest stream may become susceptible to unfamiliar
parasites and diseases, but the real danger is that they may infect native
fish with exotic parasites or diseases. And, aquarium fishes may affect
the genetics of native species by hybridizing with them. Some aquarium
species may even pose a physical or public health threat, such as
piranhas and freshwater stingrays. For more information, go to and click on "Invasive Species Threaten
America's Biological Heritage."

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