From: Karen Claxon
Subject: USGS Scientists Find New Population of Asian Swamp Eels in South
Florida
USGS Scientists Find New Population of Asian Swamp Eels in South Florida
http://biology.usgs.gov/pr/newsrelease/2000/3-3.html
U.S. Department of the Interior
U.S. Geological SurveyAddress
7920 NW 71st St.
Gainesville, FL 32653-3071
Release
March 3, 2000
Contact
John Curnutt
Hannah Hamilton
Phone
305-348-2637
352-378-8181 x 341
Fax
305-348-6883
352-373-5763
Email
john_curnutt@usgs.gov
hannah_hamilton@usgs.gov
USGS Scientists Find New Population of Asian Swamp Eels in South Florida
NOTE TO NEWS EDITORS: Reproducible photos of Asian swamp eels may be foun=
d
at:
http://biology.usgs.gov/pr/newsrelease/1998/6-15eel1.tif
http://biology.usgs.gov/pr/newsrelease/1998/6-15eel2.tif
http://biology.usgs.gov/pr/newsrelease/1998/6-15eel3.tif
http://biology.usgs.gov/pr/newsrelease/1998/6-15eel4.tif
A new population of non-native Asian swamp eels, a highly adaptable
predatory fish, has been found near the eastern border of Everglades
National Park in the area of Homestead, Fla. According to the USGS
biologists who discovered this new population in December, the eels appea=
r
to represent a separate introduction from previously discovered swamp eel
populations in Georgia, north Miami, and Tampa because of the widely
separated ranges and apparent genetic differences between the Homestead
population and the north Miami and Georgia populations.
The eels have not been found within Everglades National Park, although th=
e
latest discovery places the eels within a kilometer of the park boundary,
said Dr. John Curnutt, a biologist with the USGS Florida Caribbean Scienc=
e
Center in Miami, who is coordinating the monitoring studies of this new
population.
"These fishes have the attributes necessary to successfully invade and
colonize the Everglades and other freshwater southeastern wetlands, where
they could adversely affect native fishes, amphibians and invertebrates
through predation," said Curnutt. "They have the potential to disrupt foo=
d
webs, eat native species, and compete with native fish and wading birds f=
or
food. The interconnectedness of the waterways and the eel's biology pose
substantial risks of the species becoming established in the Everglades."
Biologists have been monitoring the distribution of this new population
since its discovery in December and are studying the effects on native
species of the swamp eels discovered last year in Florida.
Of particular concern to scientists and resource managers is that these
highly adaptable eels have the ability to thrive in a wide variety of
natural habitats and in adverse conditions. In addition to marsh and swam=
p
habitats, Curnutt said the fish survives quite well in ponds, canals,
roadside ditches and rice fields =97 "just about any freshwater habitat w=
ith a
few inches of water."
Another trait that could help these fish successful colonize southeastern
waterways is that swamp eels are air breathers, enabling them to survive
long dry spells. In fact, said Curnutt, their use of air is so efficient
that the eels can readily migrate short distances across land from one wa=
ter
body to another. In addition, the eels can live easily in even a few inch=
es
of water, especially in warm water.
Swamp eels, which reach lengths of three feet or more, are predators,
feeding on animals such as worms, insects, shrimp, crayfish and other fis=
hes
and frogs. Yet, said Curnutt, the eels are also able to survive weeks =97=
and
possibly months =97 without food. The eels are highly secretive, with mos=
t of
their activities occurring at night. In the day, the fishes hide in thick
aquatic vegetation or in small burrows and crevices along the water's edg=
e.
In many populations, all young are hatched as females, and then, after
spending part of their life as females, some eels transform into large
males.
At first, said Curnutt, biologists believed that the Homestead population
represented a range expansion by animals from the population known to exi=
st
around the Miami-Dade/Broward County line, but recently completed genetic
tests at Florida International University indicate that the Homestead
population differs genetically from eels in northern Miami-Dade. The newl=
y
discovered Homestead population is genetically closer to animals from
populations originating in southeast Asia, whereas the populations found
previously in the Miami and the Tampa areas are nearly identical to sampl=
es
from more northern parts of China.
To determine the abundance and more precise distribution of this populati=
on,
USGS biologists are collaborating with partners in the Florida Fish and
Wildlife Conservation Commission, National Park Service, Florida
International University, South Florida Water Management District, and th=
e
U.S. Fish and Wildlife Service to perform rapid monitoring. This program,
funded by the Department of the Interior's South Florida Restoration
program, is now under way, said Curnutt, and the results will help to
determine resource managers' options for trying to contain or eradicate t=
he
eel before it can enter the national park.
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 th=
ey
do not migrate to the ocean to spawn. The species introduced to Florida i=
s
native to tropical, subtropical and somewhat temperate climates in Easter=
n
Asia. In Asia, the eel is a popular food fish. In North America, the spec=
ies
is sometimes kept as an aquarium 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, scientif=
ic
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 natio=
n's
natural resources, and to enhance the quality of life by monitoring water=
,
biological, energy, and mineral resources.
***USGS***
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Last Updated: Thursday, 02-Mar-2000 14:59:22 MST