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A very Bad thing

From: djf0 <djf0 at emtc_er.usgs.gov>
Date: Fri, Jun 26, 1998 09:06 EDT
Message-id: <35939CCC.91171970 at emtc_er.usgs.gov>

U.S. Geological Survey
Florida Caribbean Science Center
7920 NW 71 Street
Gainesville, FL  32653-3071

Contact:  Hannah Hamilton  (352) 378-8181, Hannah_Hamilton at usgs_gov
Catherine Puckett Haecker (703) 648-4283, Catherine_Haecker at usgs_gov

For Release:  June 25, 1998


The Asian swamp eel, a non-native fish, has been found in canals,
ditches, streams and ponds near Tampa and Miami, Fla.  The species is
spreading and has the capability of invading and harming freshwater
ecosystems throughout the Southeast, including the already-besieged
Everglades system, according to the U.S. Geological Survey scientists
who found the species in Florida.

The exotic creature is a highly adaptable predator, able to breathe air
and to live easily in even a few inches of water, especially in warm

"This species exhibits unusual behavior, appearance and adaptations,"
said Dr. Leo Nico, a biologist with the USGS Florida Caribbean Science
Center in Gainesville, Fla.  "It has the potential to spread into
freshwater ecosystems throughout the Southeast where it could compete
with or prey upon native fishes.  Imagine a creature with all the
attributes necessary to successfully invade and colonize the Everglades
and other southeastern wetlands.  Well, the swamp eel may be that

The lakes, streams, canals and swamps of Florida and the Southeast are
ideal habitats for these eels, said Nico, who discovered the species
while conducting scientific samples of fish species in a Tampa Bay
drainage. Scientists say they suspect the swamp eel may have escaped
from a tropical fish farm or have been a pet released from an aquarium.
The species, they believe,  is already firmly established in Florida.

Although few non-native fishes invade natural wetlands -- instead being
primarily found in disturbed habitats such as canals and drainage
ditches -- Nico said the swamp eel's biology makes it well suited for
all kinds of habitats.  "We expect this foreign fish to rapidly occupy
natural wetland habitats," said Nico.  "One major concern is for the
Everglades ecosystem, not only Everglades National Park and Big Cypress
National Preserve, but the surrounding wetlands as well.  At this point,
the best outlook would be if the eel becomes a favorite food item of
native predators such as alligators or water snakes."

Swamp eels -- or rice eels as they are sometimes called -- were first
discovered in Florida waters in 1997 in two widely separated sites.  In
late summer 1997, USGS researchers  discovered a population of swamp
eels while sampling fishes in ditches, canals and streams flowing into
Tampa Bay on Florida's Gulf Coast.  At about the same time, students
from Florida International University in Miami netted several small
swamp eels while collecting aquatic plants from an artificial lake just
north of Miami.  By now, several dozen eels have been found in the Tampa
Bay area and several hundred in Miami waterways.

To determine the size and extent of the swamp eel population in Florida,
USGS researchers, working with investigators from Florida International
University and biologists from the Florida Game and Freshwater Fish
Commission, are actively searching waters surrounding the two sites
where the eels were previously found.

In May,  USGS biologists found swamp eels in samples they took
throughout a major east-west canal near the Dade-Broward County line,
including a site near the canal's border with Everglades marsh habitat.
Biologists have not found the Asian swamp eel in  interior wetlands of
the Everglades or other natural wetland systems, but the
interconnectedness of the waterways and the eel's biology pose
substantial risks of the species becoming established there, Nico said.

In North America, the species is sometimes kept as an aquarium fish,
although scientists can only speculate that the species may have escaped
or been released into the state's waters. In 1995, swamp eels were found
in several ponds at the Chattahoochee Nature Center north of Atlanta,
Ga., but USGS biologists are unaware of any possible links between the
Georgia and Florida populations.  In Georgia, scientists suspect the
swamp eel may have spread to other parts of the Chattahoochee River
system.  To determine if this is true, University of Georgia scientists,
in coordination with the National Park Service, are sampling the
Chattahoochee system.  In Georgia, entire groups of fish have
disappeared from one impoundment populated by the eels, making Florida
scientists especially aware of the potential effect of this species on
the state's native fish communities.

Of particular concern to scientists and resource managers is the ability
of swamp eels to thrive in a wide variety of natural habitats and in
adverse conditions.  In addition to marsh and swamp habitats, Nico said
the fish survives quite well in ponds, canals, roadside ditches and rice
fields -- "just about any freshwater habitat with a few inches of

Another trait that could help these fish successfully colonize
southeastern waterways is that swamp eels are air breathers, enabling
them to survive long dry spells.  In fact, said Nico, their use of air
is so efficient that the eels can readily migrate short distances across
land from one water body to another.

Swamp eels, which reach lengths of three feet or more, are predators,
feeding on animals such as worms, insects, shrimp, crayfish, other
fishes and frogs. Yet, said Nico, the eels are also able to survive
weeks -- and possibly months -- without food.  The eels are highly
secretive, with most of their activities occurring at night. In the day,
the fish hide in thick aquatic vegetation or in small burrows and
crevices along the water's edge. In many populations, all young are
hatched as females.  Then, after
spending part of their life as females, the eels transform into large

Swamp eels belong to the family Synbranchidae, a group of fishes found
in fresh and brackish waters in Central and South America, Africa, and
from India east to Australia.  These fish are not true eels, in part
because they do not migrate to the ocean to spawn.  The species
introduced to Florida has been tentatively identified as Monopterus
albus, a species native to tropical, subtropical and somewhat temperate
climates in Eastern Asia.  In Asia, the eel is a popular food fish.

As the nation's largest water, earth and biological science and civilian
mapping agency, the USGS works in cooperation with more than 2000
organizations across the country to provide reliable, impartial,
scientific information to resource managers, planners, and other
customers. This information is gathered in every state by USGS
scientists to minimize the loss of life and property from natural
disasters, to contribute to the conservation and the sound economic and
physical development of the nation's natural resources, and to enhance
the quality of life by monitoring water, biological, energy, and mineral


NOTE TO NEWS EDITORS: Reproducible pictures of the swamp eel may be
found at http://biology.usgs.gov/pr/newsrelease/1998/6-15.html

This press release and in-depth information about USGS programs may be
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