Operation Sex Change

Imagine waking up to discover that your mother, your sister, and your friends’ wives are all men. That could be reality for invasive fish if a radical plan to exterminate them takes shape.

By Cynthia Mills

John Teem and Juan Gutierrez have a bizarre solution to an intractable problem: They want to eradicate invasive fish populations from the inside out by using transvestite fish.

In all fairness, “transvestite” isn’t their term of choice. They call these fish intersex. In some cases, they might look like normal females, but they have the chromosomes of a male. Teem and Gutierrez believe that if they can dupe normal fish into mating with these gender-bent fish, they can kick off a chromosomal cascade, skewing the entire population until it consists entirely of males—effectively wiping it out.
It’s the kind of bizarre idea that brings to mind the old Kinks hit “Lola”—or even a bit of twisted science fiction. But Teem and Gutierrez might just be on to something. And while right now it’s only a plan on paper, it may quite possibly be the best plan we’ve got.

The earth is plagued everywhere with invasive species, but it would not be a stretch to say that fish are among the most intransigent of all. From Nile perch that have crowded out or eaten nearly all the cichlids in Africa’s Lake Victoria to Asian carp that have taken over whole sections of the Mississippi River, invasive fish have wreaked havoc on ecosystems and economies worldwide.

But researchers can’t find a way to eliminate these ecological scourges. Around the world, fisheries biologists have spent years hunting for a remedy that can zero in on a single species and, like a surgical air strike, eradicate it without collateral damage. To date, however, they have come up with only blunt tools—such as poisoning the water with rotenone. Ostensibly organic because it comes from tropical plants, rotenone is nonetheless lethal; a lake treated with the chemical is effectively purged of all life, including fish, crustaceans, and insects. The few other tactics biologists have pursued—including fish bounties and genetically modified fish that produce sterile offspring—also have severe limitations.

As the quest for the holy grail of invasive species eradication rolls onward, Teem and Gutierrez might have a leg up on the scientific establishment. Neither has the standard fisheries biologist’s résumé. In fact, in neither one’s background is there a shred of evidence that he would end up concerned with fish at all, much less transvestite fish.  But science is like that; often it takes someone with a fresh, even naïve perspective to see past conventional wisdom. 

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