Asian carp invasion threatens Great Lakes fishery

With fisheries on the line, Canada hopes high-tech measures can stop Asian carp

Attack of the alien carp

Benjamin Lowy/Getty Images

Asian carp, imported into the southern U.S. decades ago, have been pushing north up the Mississippi ever since flooding gave the invasive species a chance to make a break for it in the 1970s. Now the voracious eaters are poised to slip into the Great Lakes, which could mean both environmental disaster and the ruin of a multi-billion-dollar fishery. So this week the Canadian government announced it will pour $17.5 million into high-tech measures designed to keep the scaly pests out of our waters. Might as well call Canada’s new program of forensic early-detection what it is—CSI: Carp.

The two species in question—silver carp, known for leaping high up from the waters when disturbed, and bighead carp—have already appeared in Lake Michigan, gaining access mainly through the Chicago Sanitary and Ship Canal, where a series of electrically charged fences can occasionally malfunction. In the past, detecting unwanted aquatic critters has required a series of strategically placed nets, a less-than-perfect gambit. But experts believe the new federal dollars will go in part toward just-developed DNA probing techniques.

“This is all done using advanced molecular methods,” says Hugh MacIsaac, an invasive species biologist at the University of Windsor. “You don’t catch the carp, you just get the water it’s been swimming in and process it for DNA.”

The method depends on the specific genetic fingerprint for Asian carp uncovered by a team of Univesity of Notre Dame scientists in 2010. Once detected, the carp can be rooted out or poisoned. Speed is key.

“They’re very likely to invade if given sufficient opportunity,” says Tony Ricciardi, an invasive species biologist at McGill University. “It’s not an experiment I’d like to try.”

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