CHICAGO _ On a bleak and biting December morning, a team of state-contracted commercial fishermen at Starved Rock Marina slipped into their waders, salted down their johnboats to protect against ice and launched onto the Illinois River.
Armed with thousands of yards of netting, the fleet set course for a cove at Sheehan Island where they suspected a horde of silver and bighead carp, the most abundant and worrisome species of invasive Asian carp, were holed up for the winter.
Within less than a half-hour, the fishermen transformed the inlet, which is big enough to hold Millennium Park, into an enormous booby trap, layering netting from the shores to the mouth of the bay. Once they were finished, the stillness of the muted winter morning was broken by the fishermen collectively revving their motors, driving frenzied Asian carp into the nets.
While state and federal officials debate costly preventive measures, unreliable electrical barriers near Romeoville serve as the last rampart blocking these Asian carp from entering the Great Lakes. In the meantime, the Illinois Department of Natural Resources has been testing alternative approaches.
Kevin Irons, the manager for the aquatic nuisance species program at the Illinois DNR, has traveled to the Asian carp's native China three times, most recently in October. There, he learned how teams of fishermen methodically captured the fish each year by strategically casting their nets to divide waterways and scoop up carp sector by sector in multiday campaigns.
Irons has shared this technique with commercial fishermen contracted by Illinois who have added their own twist. In China, they fish quietly, but Illinois' "carp cowboys" are exploiting the species' fear of loud noises using golf clubs, baseball bats and even plungers to bang on the sides of their boats, essentially herding the fish into their nets _ often tens of thousands of pounds at a time.
"Our fishermen didn't quite have the patience. It's kind of like a cattle drive in the water," he said.
But similar to the Chinese, local fishermen are employing a common strategy and working together over an extended period of time.
"They want to harvest the whole lake. We want to harvest the whole river to remove them, so now we're working together like a small strike team," Irons said.
Ironically, Chinese researchers studying conservation have also traveled to Illinois, in part to study why carp are thriving in the Midwest.
The populations of silver and bighead carp are declining in China, where it is a common food source, and becoming threatened due to a combination of overfishing, pollution and the construction of a colossal hydroelectric dam. The problem has gotten so dire that Chinese officials plan to implement a year-round ban on commercial fishing in the Yangtze River by 2020, Irons said.
