> G'day folks
> Thought some of you might find this interesting.
> From Wired Magazine, available online at:
> The Plot to Kill the Carp
> Scientists are lab-testing a death fish that will wipe out its own
> species. Pests across the planet beware.
> By Todd Woody
> The dirt road that snakes up into the Tasmanian highlands is rutted
> from generations of Australian anglers who trekked to the shores of
> what was once a vast crystalline lake. But today, there's not a soul
> in sight. I park my rented Hyundai and go walkabout. The only sound is
> the wind through the lake's desiccated marshes, wetlands that used to
> echo with the splash of platypus and the chatter of native birds and
> frogs. The silence is broken by a pickup truck rattling down the road
> toward me. "You all right, mate?" asks the driver, surprised to see
> anyone at Lake Crescent. I nod. I haven't come to fish but to witness
> the ecological devastation wrought by an alien invasion.
> The aliens in question: European carp. Wildlife officials discovered
> them swimming among the lake's rare native fish seven years ago and
> wasted no time taking drastic action by quarantining the area.
> Opportunistic and adaptable, Cyrprinus carpio uproots aquatic
> vegetation and turns clear-running water into a muddy morass,
> depriving native fish of food, light, and oxygen. To save Lake
> Crescent, government authorities had to partially destroy it by
> lowering water levels, denying the carp space to spawn. The invader
> — likely the descendant of juveniles used as fishing bait —
> has been held in check but are not yet eradicated.
> The planet's most farmed fish and a staple of Asian diets, carp are
> the Borg of the fish world, infiltrating lakes and rivers from China
> to California. In Australia, they are reviled for the environmental
> destruction caused by their prolific breeding. The so-called river
> rabbits have come to dominate the country's waterways since they were
> released into the wild a century ago.
> Now, for the first time anywhere, Australian scientists have a plan to
> genetically engineer carp out of existence. Injected with
> "daughterless" genes, the fish will produce only male offspring and
> thus spawn the seeds of their own destruction. As these doomsday carp
> mate with their wild cousins, the population of each targeted river or
> lake will eventually drive itself to extinction.
> First, though, there are smaller fish to fry. Two hours south of Lake
> Crescent is the government's marine research center in Hobart, the
> capital of the island state of Tasmania. Biologist Ron Thresher ushers
> me into a nondescript laboratory. When he raps the lab's thick, tinted
> windows, there's a distinctive thud. "Bulletproof," he says. The
> floors, I notice, slope downward. "Every drop of water that comes out
> of here gets sterilized." These safeguards keep outsiders from
> absconding with genetically engineered fish and prevent tainted water
> from escaping the lab.
> The subject of all this security is darting about a tank lining one
> wall of an inner chamber: the 2-inch-long zebra fish, an unexceptional
> aquarium dweller procured from a local pet store — except that
> some of these translucent striped fish carry prototypes of the
> daughterless gene in their gonads. If all goes well, construction of
> the daughterless carp will begin within two years.
> INVASIVE SPECIES COST BILLIONS IN THE US ALONE. THE CURE:
> "DAUGHTERLESS" GENES.
> Genetic engineering offers a solution to the feral peril that has
> plagued the region since Captain Cook released a pair of pigs in
> Tasmania in 1777. As Thresher tinkers with fish genes, researchers on
> the mainland are studying ways to sterilize foxes and other foreign
> mammals. With dozens of indigenous animals teetering on the brink of
> oblivion, scientists are racing the clock for a tech fix to the
> problem of invasive species, which threatens biodiversity worldwide
> and costs the US alone more than $138 billion a year. But will the
> cure be worse than the disease?
> When the British First Fleet sailed into Sydney Cove on January 26,
> 1788, its cargo of convicts encountered a fantastical landscape. Oddly
> angled trees shed not their leaves but their bark, while furred
> animals of strange proportions hopped, burrowed, and laid eggs. The
> colonists set out to remake the Australian bush into a facsimile of
> the English countryside, populating the land with rabbits, goats, and
> other familiar creatures they'd brought from home. To complete the
> pastoral tableau, the local gentry imported the red fox so that the
> antipodean woodlands would echo with the braying of hounds on the
> The result was a marsupial massacre. With few competitors, the fox and
> feral cat ate their way across the continent, finding the pouched
> natives to be easy prey. Goats and rabbits, meanwhile, denuded the
> terrain of food and shelter. The invasion has contributed to
> Australia's appalling extinction rate — at least 18 native mammal
> species have been lost since European settlement, more than in any
> other country.
> The reach of the fox and its fellow transplants is stunning. I've
> spotted foxes on remote west coast beaches waiting for green sea
> turtles to come ashore. Wild camels have towered over my Toyota in the
> central desert, and I've stumbled across the muddy wallows of feral
> pigs in primeval rain forests of the tropical north.
> Australians have been battling nonnative pests with mixed success
> since colonial days. Just 30 years after unleashing the fox, the
> government put a bounty on its head. In the 20th century, government
> scientists bombarded foxes with poisoned kangaroo meat and released a
> virus deadly to Aussie rabbits.
> Fixing one feral problem often triggers another. When foxes were
> eradicated from a west coast peninsula two years ago, the cat
> population soared. Some of Australia's most intractable nonnative
> species are those deliberately let loose to control another pest. In
> 1935, the government imported cane toads, thinking the amphibian would
> eat a beetle that was blighting the sugar cane crop. The cane toad ate
> everything but. Spreading through Australia like a biblical plague,
> the toad, which secretes a deadly poison, devastated native wildlife.
> The diminutive Central American mosquito fish — introduced to
> control winged bloodsuckers — has become the cane toad of the
> waterways, eating the eggs of Australia's fish but showing scant
> interest in mosquito larvae. After the zebra fish, the mosquito fish
> is next up for the daughterless treatment. And then there are the
> carp, which have decimated habitats and dominated native fish in the
> race for food. In the country's largest river system, the
> Murray-Darling Basin in southeast Australia, carp now constitute 90
> percent of the fish biomass. "There are between 30 and 40 native
> species in the river. About half of them are at lower levels with some
> threat of extinction," says Kevin Goss, an executive with the
> Murray-Darling Basin Commission.
> If anything, aquatic invaders have proven even more difficult to
> eradicate than foxes. You can't poison carp without putting native
> fish at risk. The answer: Program the carp to self-destruct.
> Separated from mainland Australia by 150 miles of ocean that rose
> after the last Ice Age, the Ohio-sized island of Tasmania was once the
> end of the world. It was home to Australia's most feared penal colony,
> whose overlords were obsessed with keeping the British Empire's worst
> convicts from escaping. Today, preserving Tasmania's abundant
> biodiversity means holding the outside world at bay. Luck and distance
> kept Tasmania largely free of destructive species in the 19th century.
> Today, ecological disaster is just a ferry ride away.
> As I drive down a deserted highway, logging trucks rumble by, and the
> Twin Peaks soundtrack plays in my head. The thickly forested landscape
> conjures up images from Richard Flanagan's Gould's Book of Fish, a
> phantasmagoric account of a barbarous 19th-century Tasmanian penal
> settlement on "an island in the middle of a wilderness far off the
> coast of a nowhere land so blighted it existed only as a gaol." I find
> myself imagining mad scientists reanimating mutant fish on the
> expanses of Tasmania's still-unexplored wild lands.
> It's a bit of a letdown, then, to meet Ron Thresher, a laid-back
> 53-year-old American immigrant. Dressed in jeans, sweater, and boots,
> the lanky fish biologist looks as if he would be just as at home in
> Boulder or Santa Cruz as at the marine lab on the Hobart waterfront,
> operated by the government's Commonwealth Scientific Industrial
> Research Organization. The New York native came to Australia in 1979
> on a postdoc. About eight years ago, Thresher joined a CSIRO division
> established to control marine pests. As global trade intensified in
> the 1990s, so did the number of unwanted overseas visitors hitching
> rides to Australia in ballast water. But by then the idea of
> introducing a supposedly benign foreign species to control a
> destructive one had become anathema. Rapid advances in genetics
> pointed to a new approach. Thresher's team spent several years
> modeling different population-busting scenarios before they had their
> eureka moment. Biologists have long known that female fish develop
> when an enzyme called aromatase transforms androgen into estrogen.
> It's been possible to chemically block aromatase to produce only
> males. "Where we were clever is that we figured out a way to make it
> an inheritable characteristic," Thresher says.
> To prove the concept, the scientists concocted a daughterless gene for
> the zebra fish, a cousin of the carp. First they located the gene that
> produces aromatase. Then they sequenced that gene in reverse —
> creating a blocker that binds to and neutralizes the aromatase gene.
> Thresher tested the new gene by injecting it into zebra fish eggs. The
> result: Eighty percent of the brood was born male — a striking
> success given that some of the daughterless genes are inevitably
> destroyed during the injection process. The Murray-Darling Basin
> Commission subsequently enlisted Thresher to develop a daughterless
> Phase two, now under way, is the creation of a daughterless mosquito
> fish. A handful of the 1½-inch-long drab but destructive species
> are swimming around a small tank in Thresher's lab. The fast-breeding
> fish — they become sexually mature at two weeks — will allow
> Thresher's team to evaluate how (and if) the daughterless gene spreads
> through the population generation after generation. That'll give
> Thresher the chance to work out any kinks before constructing a
> daughterless gene for the carp, which takes two years to reach
> reproductive age. Three years of mosquito fish lab trials will be
> followed by field tests in high-security ponds on the mainland. If all
> goes well, genetically modified mosquito fish will be released to
> eradicate a targeted fish population.
> NIGHTMARE SCENARIO: THE CARP ESCAPE AND CROSSBREED — OR EVOLVE
> INTO SUPERPESTS.
> The mosquito fish trials will help resolve the many unknowns about
> releasing these terminator animals into nature. How many daughterless
> genes should the carp carry? Just how many doomsday carp — and
> how long — will it take to eliminate a wild population? Will the
> daughterless genes "jump" to other species?
> The answers will be supplied in part by a computer model — called
> Carpmod — that will simulate the Murray-Darling Basin. "You have
> an underlying series of equations that represent how fish move from
> one area to another," explains CSIRO ecosystem modeler Nic Bax. "Given
> that, you can release the daughterless carp, see how they're going to
> breed with fish that are there, and observe in the model how they
> spread." The model will first look at daughterless mosquito fish. As
> the fish move from lab to pond to lake, the program will be
> continually refined as its predictions are tested in the field.
> Aussie environmentalists are skeptical that a computer can replicate
> wild Australia. "We're all too aware that things don't always end up
> operating in nature the way they do in a laboratory experiment,"
> cautions Bob Phelps, director of the Australian Gene Ethics Network.
> "To talk about the release of millions of genetically engineered fish
> into complex ecological systems and know what the upshot will be is
> impossible." The nightmare scenario: Daughterless carp somehow escape
> to other parts of the world and breed with dozens of closely related
> species. Or they evolve in unforeseen ways into superpests.
> For the moment, the carp project is attracting little attention from
> Australian enviros. Expect a bigger fight from American greens if the
> technology is exported across the Pacific. "Sierra Club has called for
> a moratorium on all releases of genetically engineered organisms,"
> says Sierra Club activist Laurel Hopwood, who is fighting to keep
> genetically altered salmon off American dinner plates.
> Thresher insists the daughterless carp will not be a frankenfish.
> "When we build this for carp, it will be from 100 percent carp genes.
> We'll just be rearranging them to achieve what we want." He
> anticipates the next question. "'Omigod, what if someone sneaks one of
> these carp to Europe? Are you going to endanger the species globally?'
> The short answer is no. If someone snuck a thousand of these things to
> Europe and released them into the Danube, it really wouldn't make a
> significant impact," he says.
> He figures the math will work this way: To eliminate carp from a
> river, you need to introduce daughterless carp at a rate equal to
> between 0.5 percent and 1 percent of the total population each year
> for 20 years. So a lake with 100,000 wild carp would need to be
> stocked with 500 to 1,000 daughterless carp annually. Presumably, you
> could speed up the process by introducing additional modified carp.
> "If three years into the exercise we suddenly find the thing has
> jumped to Australian bass, we can stop stocking it. And the gene will
> eventually be overwhelmed by the wild type," he says. "There is plenty
> of time to launch a counter-gene." It would take two decades to wipe
> out the carp. Or maybe longer. Anne Kapuscinski, a University of
> Minnesota geneticist and a leading expert on transgenic fish, suspects
> the complex dynamics of fish populations and genetics may resist a
> daughterless assault. Nature could conspire to give the carp a higher
> survival rate or simply turn off the daughterless gene.
> Globalization means no island is an island anymore. As Thresher and I
> talk carp, foxes — smuggled in from the mainland — are
> roaming the Tasmanian bush and may be establishing a beachhead. "If
> foxes aren't eradicated soon, we'll have a drumroll of extinctions,"
> warns wildlife officer Nick Mooney. Australian government scientists
> are working on a noncontagious virus that will carry a DNA sequence
> designed to sterilize foxes. A similar but contagious
> immunocontraceptive technique is being tested on Aussie rabbits.
> With destructive alien species expanding worldwide, such genetic
> technology is likely to spread like, well, carp. The insatiable
> northern snakehead fish — a native of China that can breathe air
> and walk on land — has been multiplying in a Maryland pond. The
> Great Lakes have been invaded by more aliens than those in a Star Wars
> bar scene. If zebra mussels and round gobies weren't wreaking havoc
> enough, Charles Krueger, science director of the Great Lakes Fishery
> Commission, now has to contend with the big head carp, a 50-pound
> monster from China. "We are certainly interested in daughterless gene
> technology," says Krueger. "Our primary concern is if somehow that
> technology got back to the species' native distribution."
> It will probably be seven more years before the doomsday carp is ready
> to swim wild. But ask Ron Thresher about the future of the
> daughterless gene, and he rattles off a list of possible candidates:
> snails, cane toads, birds maybe. And foxes? "In theory, it could work
> on mammals, although you would have to use different genes. Sexual
> development in mammals is much, much, much more complicated than in
> fish." He pauses. "It may well work on something like cats and foxes.
> I'd be quite keen to pursue that." With the tools of genetic
> manipulation in his grasp, it's only a matter of carpe diem.
> Copyright (C) 1993-99 The Conde Nast Publications Inc. All rights
/"Unless stated otherwise, comments made on this list do not necessarily
/ reflect the beliefs or goals of the North American Native Fishes
/ This is the discussion list of the North American Native Fishes Association
/ nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word
/ subscribe, unsubscribe, or help in the body (not subject) of an email to
/ nanfa-request_at_aquaria.net. For a digest version, send the command to
/ nanfa-digest-request_at_aquaria.net instead.
/ For more information about NANFA, visit our web page, http://www.nanfa.org