Taking on Asian carp with pills, lure of sex
What weapon is left to battle those disgusting, flopping, ravenous, destructive, proliferating Asian carp?
Time to go old school, with a Trojan horse. Actually, it’s a Wisconsin horse - a deliciously devious one, at that. Scientists there are scheming to create an itty-bitty poison pill that Asian carp will unknowingly eat as their last meal - yet won’t hurt other fish.
Nothing else - netting, harvesting, zapping - seems to stem the explosion of the slimy invaders. That’s why the U.S. Geological Survey in LaCrosse, Wis., has initiated unique research into a sneaky solution.
“We’re still in the initial stages of deciding if the concept will work,” says biologist Jon Amberg. “Things look promising.”
There are four types of Asian carp. Two - silver and big head - have been the most problematic. They’re the kind taking over the Illinois River, those fat wigglers that leap out of the water and plop into boats, leaving bloody goo behind.
It’s hard to pinpoint a target with poison. Even in a controlled area - say, a bay - any lethal chemical dumped into the water will kill just about every species, not just Asian carp.
But Amberg and his colleagues wonder if they can slip ‘em a Mickey.
Common carp are known as detritivores: bottom-feeders that eat garbage and refuse. But silver and big head carp are filter feeders: swimming open-mouth, they ingest algae, plankton and other small substances as water passes through their mouths and gills.
The Wisconsin research looks to create a super-small pill, with a diameter smaller than that of a human hair. Inside the pill is a toxin, such as common fish-killers rotenone or antimycin. In that small of a dose, the chemical wouldn’t affect an Asian carp. But as the filter feeders eat a lot of the pills - say, 2,000 or so - they’d die.
Meantime, other fish in the Illinois or Great Lakes - such as bass or walleye or whatever - won’t consume many of the pills, because they’re herbivores or carnivores. As the Asian carp ingest their fatal dose, other fish might consume maybe five pills - non-lethal to them or anglers who catch and eat them.
At least, that’s the theory. Skeptics worry about an overload of poison in environment or human digestive tracts. Amberg says the poisons degrade fast in natural settings, and the pills would be spread into waterways only in a controlled manner.
And to limit the effect on other species, the pills would be coated with a substance that would break down only inside Asian carp. Preliminary research shows that enzymes unique to that breed might be the key: The pill coating would dissolve only in Asian carp. Thus, the pill would be lethal only to that species.
And the caper gets even more cunning. Amberg says the Asian carp would be lured to a bay or other controlled area with sex pheromones, tricking a mass response with the fake promise of mating.
“That’s a major drive for a lot of animals,” Amberg says. “We make a lot of decisions on the basis of that.”
Once in the bay, the focus would be switched to a food supply - a nice consolation prize. As the fish eat yummy algae and whatnot, the pills would be released. Bye-bye.
“They’d be deceased in a day,” Amberg says.
Another possibility: Infuse the pill not with poison, but birth control. That way, Amberg says, the species could be winnowed, not destroyed. Again, more research is needed to see whether fish birth control could hurt other critters or people.
The concerns and testing are great. There’s no timetable. But, with Asian carp spreading every day, the biologists work with a sense of urgency.
“We’re moving on pretty quickly,” Amberg says. “We’re moving along as fast as possible. But we want to make sure the science behind it is solid.”
And if it works? Well, then it’s time for more worry - thanks to the other two types of Asian carp.
Right now, grass carp aren’t a big deal, at least not around here. But they eat plants and just about anything else. A lot.
“They’re kind of like goats,” Amberg says.
And there’s also black carp, which chomp mussels. Like the grass carp, you find them in very small populations, mostly where the Illinois River pours into the Mississippi.
But neither the grass carp or black carp would be pill-eaters. So, another solution would be needed there.
Then, back to the drawing board in the endless war against Asian carp.
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Topic: Taking on carp w/ sex (Read 2151 times)
