This article on Asian Swamp Eels struck me as one which some other
extropians might enjoy. Specifically, I was wondering if anyone has any
ideas on how their expansion could be slowed or stopped. They're amazingly
resilient, as you'll see below.
Best wishes to all,
Bill Douglass
September 27, 2000
A Plague of Asian Eels Highlights
The Damage From Foreign Species
By MARK ROBICHAUX
Staff Reporter of THE WALL STREET JOURNAL
MIRAMAR, Fla. -- An aluminum boat carrying federal
biologists roars down Canal C-9, a 20-mile-long
waterway that passes a stone's throw from Pro Player
Stadium, home of the Miami Dolphins.
The boat, which is equipped with an "electro-fishing
unit," slows to a stop, and one of the men lowers two
chandeliers of thick wires into the water. With the
press of a pedal, he unleashes up to 800 volts into
the murky depths. The scientists are stalking one of
the newest, most indestructible aquatic predators in
the U.S.: the Asian swamp eel.
The more scientists learn about the eel, Monopterus
albus, the more discouraged they become about stopping
it. Here is what is known so far: It has a bottomless
appetite for any aquatic life in its path -- fish,
frogs, shrimp, crayfish and insects. A nocturnal
hunter, it is rarely seen by humans. The
three-foot-long adults have no known natural enemies,
with the possible exception of alligators.
By Land or by Sea
The eel's most alarming trait, though, is its uncanny
ability to survive extreme conditions. In one study by
a Harvard zoologist, an Asian swamp eel lived seven
months in a damp towel without food or water. The
olive-brown creature prefers tropical waters, yet it
can flourish in sub-zero temperatures. It prefers
fresh water but can tolerate high salinity. It
breathes under water like a fish, but can slither
across dry land, sometimes in packs of 50 or more,
sucking air through a two-holed snout. It breeds
year-round, with one eel laying as many as 1,000 eggs
at a time. No mates nearby? No problem: Almost
magically -- scientists still don't know how -- the
eel can change into a female from a male. Even more of
a riddle is how to kill the eel: It thus far appears
almost immune to poisons and dynamite.
Asian swamp eel
"We can't find a chink in its armor," says Leo Nico, a
biologist with the U.S. Geological Survey, the
nation's largest water, earth and biological science
agency.
As if this weren't cause enough for concern, the eel
is now within a mile of the ecologically fragile
Everglades National Park, a 1.5 million-acre oasis of
rare plants, animals and fish, and the subtropical
jewel of America's park system. If the eels reach the
park, there's a chance they could start gobbling their
way through one of America's most-threatened
ecosystems.
The tale of the eel's discovery in the U.S. offers a
window into one of the most vexing problems facing the
environment in America today, rivaling wildfires,
logging, flooding, earthquakes or tornadoes in sheer
economic damage -- the vast and silent explosion of
invasive species. In a trend accelerated by the
globalization of the world economy, about 50,000
introduced and invasive nonnative species have entered
the U.S. to date. Some, such as corn, wheat, rice,
cattle and poultry, proved their value to the economy
and culture long ago.
But the problems caused by other newer invaders are
taking their toll. Introduced and invasive species
cost the U.S. an estimated $138 billion annually
according to a study last year by four researchers at
Cornell University.
In Louisiana, for instance, Formosan termites chew up
historic homes in the French quarter of New Orleans
and a sheriff's SWAT team shoots beaver-size,
nonnative swamp rats from South America overtaking
drainage canals. Suppressing a 1996 infestation of
Asian long-horned beetles in New York City cost the
state and federal governments more than $4 million. In
the Great Lakes, Zebra mussels introduced by Russian
freighters in 1986 now cause an estimated $5 billion
in damage annually to pipes, boats and other
structures. Exotic weeds and plants -- a particular
nuisance to Western ranchers -- are expanding their
range at a rate of 4,600 acres a day.
The environmental cost, meanwhile, is incalculable.
Nonindigenous species disrupt delicate food webs and
upset rare breeding sites. About 42% of the species
listed as endangered or threatened under the
Endangered Species Act are there because of
competition or predation by foreign species. And
there's no end in sight: Every minute, 40,000 gallons
of ballast water are dumped into U.S. harbors, some of
it containing exotic organisms that could alter or
destroy marine ecosystems, according to the Department
of Commerce. Even baby's breath, the tiny white
flowers from Eurasia that float on a bride's veil, is
a menace to unique habitats in the West.
Concerned about the federal and state governments'
scattershot and overlapping response to the problem,
President Clinton 18 months ago signed an executive
order creating the National Invasive Species Council,
for the first time coordinating the efforts of 20
federal agencies. In a detailed "management report" to
be released next week for public comment, the council
outlines ambitious plans to create an early-detection
team, educate the public, strengthen import controls
and design an online database of species where
scientists around the world can share information.
"America's landscape is being transformed by swamp
eels, cheatgrass and a host of other creatures and
weeds that don't belong," Secretary of the Interior
Bruce Babbitt said in a written response to questions.
"The national invasive species plan now being proposed
is a big, first step in turning back this unwelcome
tide."
The Asian swamp eel would still be in hiding today
were it not for the abiding curiosity of a Smithsonian
Institution scientist named Wayne Starnes, who
discovered the eel on the North American continent.
Along the way, a hurricane, a part-time snail
specialist, a student in Jakarta, and a spontaneous
roadside stop by a piranha expert all played a crucial
role in understanding what scientists know so far
about the species.
In late September 1994, Mr. Starnes, an ichthyologist
with a Ph.D. in ecology, flew to Atlanta from his
Washington lab for a conference sponsored by the
American Zoological Association, where he was eager to
pitch a book project on freshwater fish. One evening,
on a lark, he joined his co-author, a professional
nature photographer named Dick Bryant, in a 20-minute
drive north of Atlanta to judge a nature photography
contest at the Chatahoochee Nature Center, a log-cabin
style museum surrounded by ponds and winding trails.
While touring the exhibits at night with a staffer, he
noticed a dish on a table that held a three-inch worm
as thin "as a thick pencil lead."
"Where did you get this?" he asked the staffer.
Earlier in the day, children were collecting bugs and
crawfish and "these worms" to study in the center, the
man replied. Mr. Starnes lifted the dish to his eyes.
It looked like a tiny eel, he said to himself. But
American eels wouldn't be this far inland -- they
spawn in the ocean. Was it a siren, the eel-shaped
salamander with no hind legs, or perhaps a Southern
Brook Lamprey, which is native to the Chatahoochee
River?
Dr. Starnes slipped the eel in a small vial with
formaldehyde and carried it in his briefcase back to
the lab at the Smithsonian in Washington. Adjusting
the focus of the microscope, Mr. Starnes stared at the
eel and whispered to himself, "Oh man, I've seen this
face before." It was the same family of eels he had
seen on research trips to South America and Central
America. This particular family of eels is also found
in India, African swamps and flooded rice fields in
Asia. The eels had been spotted in Hawaii years ago.
Crash Diet
To further educate himself, Mr. Starnes relied on
several early eel studies, including one by a Harvard
professor named Karel Liem, whose research reached
back to the 1960s. Prof. Liem's own first encounter
with the eels was memorable: As a graduate student at
the University of Indonesia in Jakarta, he traveled
one night in 1961 to a swamp to collect frogs for his
thesis project. Suddenly, his headlamp lit up a herd
of eels moving across land. Shocked and intrigued, "I
collected 87 live specimens in maybe less than an
hour," he said. He's studied them ever since, focusing
on their amazing resilience. In one landmark study, he
starved 40 eels for as long as seven months to gauge
their ability to survive prolonged drought and food
deprivation.
Still curious about the eels, Mr. Starnes flew back to
the nature center in Georgia in August 1996, where he
met with two men from the Georgia Department of
Natural Resources. They were armed with backpack
electro-fishing devices, which momentarily stun fish.
At the first crackle of electricity, Mr. Starnes
quickly saw the orange bellies of three-foot adult
eels as they turned rigid in the murky water. "They
were thick as hair on a dog's back in there," he
recalls. After two hours, they collected 24 eels from
three ponds. Mr. Starnes found sunfish and bass in the
eels' bellies, and the ponds were depleted of smaller
fish.
In the fall of 1997, Mr. Starnes returned to the site
with the Georgia DNR, and shocked and scooped up 19
eels. More troubling to Mr. Starnes, though, was the
fact that the tropically inclined eels had survived a
bitter winter in the Atlanta area that paved ponds
with a foot of ice. Mr. Starnes, who by then had taken
a job as research curator of fishes at the North
Carolina Science Museum, put the eels in a large tank
to observe. All of Mr. Starnes's notes jibed with Mr.
Liem's observation 40 years earlier. "The limits of
their gluttony are hard to establish," he wrote in a
paper with Mr. Bryant and others. In captivity, they
will eat "minnow after minnow." Particularly eerie was
to "walk into a room and have five ominous heads rise
to the surface, orient your presence, and follow you
about the room with almost demanding expectancy."
A second population wasn't revealed until three years
later, in June 1997, nearly 700 miles southeast of
Atlanta. A Florida International University student
named Carol Curtis was studying electric knifefish,
another exotic species. She netted several small baby
swamp eels in a pond that drains into a waterway known
as canal C-9, north of Miami. She was collecting
samples of water hyacinth, an invasive flower species,
for her aquarium. The eel found its way to FIU Prof.
Joel Trexler, who has a doctorate in biology. "The
minute I saw it, I knew it was not from here," he
said.
Yet another group of eels emerged around the same
time. While driving home to Gainesville, Fla., from a
boating seminar in St. Petersburg, Mr. Nico, the
federal biologist, wondered if the roadside ditches
held any Oriental weatherfish -- a peculiar specimen
he was researching whose behavior allegedly can
predict weather. In a rural area southeast of Tampa
Bay, he eased onto the shoulder of the road and pulled
out his pole-nets.
Killer Fire Ants
Mr. Nico, who wrote his thesis on piranhas in South
America, knew the area held promise. South Florida is
a mecca for more than 100 uninvited, or nonnative,
species. Fire ants from South America, for example,
harass homeowners, even killing an elderly woman there
earlier this year. Melaleuca trees from Australia dry
up the Everglades, lowering the water table and
creating a fire hazard. In the ditch, Mr. Nico scooped
up several Oriental weatherfish and two wriggling
eels, each about a foot long. Fascinated, he took them
back to the lab at the Florida Caribbean Science
Center, where he correctly identified them as Asian
swamp eels, a species he studied as a student in South
America.
Mr. Nico's boss, USGS branch chief Jim Williams, made
the connection with the Georgia eels immediately --
Mr. Starnes was a buddy from years back. News of the
eels spread slowly on the scientific grapevine, and a
network of scientists formed. Mr. Starnes flew down to
Florida to study specimens in the FIU lab. Meanwhile,
Prof. Trexler asked his students visiting home in
Southern China -- where eels are sold in baskets of
grass as food items -- to bring back specimens for
comparison. And Mr. Nico brought back some tissue
samples of baby eels from Venezuela.
That spring, Mr. Nico sampled the C-9 canal in North
Miami, a virtual freeway for exotic fish in Florida.
Mr. Nico and his team found "dozens of eels of all
different sizes" -- the biggest infestation yet. Mr.
Nico began surveying every month with the
electro-fishing boat, which stuns fish in a 10-foot
radius long enough to net them.
Off With Their Heads
Even with all the technology, the eels are extremely
difficult to grab. On a recent return to the site, the
boat driver yelled directions to the two men manning
the nets. "There he goes! Behind that rock! On the
bank!" On a small table on the bank, Jeffrey Herod,
clad in a long blue plastic apron, called out the
weight and length of each eel. Using a small pair of
shears, he cut off the heads, which are helpful in
gauging the eels' age. "Watch out for these boys," Mr.
Herod said to his staff. "They're bleeders."
Soon several agencies pitched in with research and
sampling, including the Florida Fish and Wildlife
Conservation Commission, the South Florida Water
Management District, the U.S. Fish and Wildlife
Service, the National Park Service, as well as the
USGS offices in the Caribbean Science Center and the
Everglades.
Despite the number of experts involved, though, basic
questions remained unanswered. How did the eel get
here? How fast and how far can it spread? How do we
get rid of it? Theories on their entry are many. The
eels could be unwanted aquarium pets dumped into the
wild -- pet stores sell baby eels nearby -- or
escapees from an aquarium-fish farm, say, during a
flood. Another theory is the eels were intentionally
introduced as food by Asian immigrants. Considered a
delicacy, the eels are cut up in sections, either
grilled or stir fried, and served over rice, usually
with a sauce.
On Sept. 23, 1998, the Florida scientists flew to
Washington to inform executives at the Department of
the Interior. Afterwards, the eels were listed by the
Aquatic Nuisance Species Task Force, a group of seven
federal agencies dedicated to control aquatic
nuisances. "The question everybody wanted answered is
this: Is there any way to keep this from getting into
the park? There was a real desire to contain it or
even eradicate it," says Prof. Trexler, who attended
the meeting. Among the ideas: a network of underwater
electronic fences in strategic locations, similar to
the ones used in the Great Lakes region to contain the
spread of lamprey eels. The interior department "took
it seriously from the beginning," says Prof. Trexler.
"They said they'd do everything they can to keep it
out of the park. I was amazed at the high level of
concern." But the meeting didn't change Mr. Nico's
mind. "I just didn't think it could be contained."
'Snakes' in the Nursery
Hurricane Irene slammed the Florida keys in the fall
of 1999, dumping more than a foot of rain in the Miami
area. In Homestead, pastures turned into lakes. Canals
flooded over banks. One alarmed owner of a nursery
reported several "snakes" around his business, where
large potted palms are sold. Bill Loftas, a senior
USGS scientist in the Everglades, investigated. He
found his first swamp eel run over in the nursery. The
next day, with Mr. Trexler, Mr. Loftas found three
dead eels and a live one. More questions demanded
attention: Had the eel moved across land? Were these
eels from the same family in Miami or in Tampa or even
Georgia? Or were they a new population?
This past winter, concerned that the eel had already
breached the park, Mr. Loftas took the electro-fishing
unit in a marsh boat and searched for hours with an
FIU postdoctoral intern. They found nothing. "But that
that doesn't mean they're not there." Like many of the
scientists studying the eel, he believes quick action
is critical. "This is not a lot of arm waving," said
Mr. Trexler. "This is a real threat."
Over Christmas, Mr. Trexler kept the eel tissue
samples from the nursery in his freezer and called Tim
Collins, snail specialist and a molecular systematist
at FIU. "Could you throw this into your works?" Mr.
Trexler asked him. Mr. Collins conducted DNA tests
through the Christmas break. "When we found the
answer, we were floored," said Mr. Trexler. The eels
were a "separate introduction" from previously
discovered populations in Georgia, North Miami, and
Tampa. After extensive DNA testing, they concluded
four different introductions of eels had occurred in
the U.S.
After a flurry of exchanged e-mails, phone calls and
faxes, state and federal biologists agreed to gather
in January at FIU to draw up a plan to deal with the
eel. Meetings continued through the winter and spring.
Today, USGS scientists, working with researchers at
FIU and biologists from the Florida Fish and Wildlife
Conservation Commission, are actively and regularly
searching waters where the eels were previously found.
The USGS is preparing a rapid response team to find
and "contain" the eel.
But killing the eels, which are estimated to number in
the tens of thousands in the U.S. now, may prove
tricky. Dynamite, a crude but effective way to kill
fish, doesn't work well on eels because they lack the
large air bladder that makes fish susceptible to
concussion blasts, and they can retreat to their
burrows. Poisoning the entire length of the infested
canals still wouldn't kill all eels. In tests using
rotenone, a poison that makes it impossible for fish
to use oxygen, the eels simply raise their snouts
above water and breathe air.
Any such efforts would certainly incite protest over
the Everglades. Just two years ago in California, the
state Game and Fish Commission poisoned Lake Davis --
the entire lake -- to rid it of northern pike, worried
they'd become a threat to native trout. Protests, loud
and long, continue today. "Which is worse?" asks Mr.
Trexler. "The spread of the invader or the risk
associated with containing it?"
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