It's Asian Carp Against the Current
Sunday, May 22, 2005
ROMEOVILLE, Ill. -- These fish jump. Oh, how they jump. It's common for an Asian carp to leap four feet out of the water and flop into whatever may rumble into its path, be it watercraft or fisherman. They also make a big splash. A 60-pounder is not unusual.
"Every day we go out on the water, the number of fish we see jumping around the boat is just astounding. It's incomprehensible," said Mark Pegg, a fisheries biologist for the Illinois Natural History Survey. "You just have to see it to realize there are that many fish jumping around you."
Near the Illinois River, Pegg and his colleagues inspected a 43-pound female, which he described as "a small one." She was carrying 2.2 million eggs, and she had plenty of company. "There were hundreds, if not thousands, of large females in this one inlet we were sampling."
The Asian carp is sowing fear in marine biologists and fishermen. Descendants of the fish, imported from China 30 years ago by catfish farmers in the deep South, escaped their pens when floodwaters rose and have been swimming north and procreating ever since, each day consuming as much as 50 percent of their body weight in plankton and other microorganisms.
The danger, experts say, is that the voracious jumping carp will overrun the waterways and other fish will starve to death. Here along the Chicago Sanitary and Ship Canal, a gateway to the Great Lakes, government authorities hope to shock the carp into submission.
At a construction cost of $9 million and an annual expense of $500,000, state and federal engineers are electrifying 500 feet of water to prevent the Asian carp from reaching Lake Michigan. Crews are using heavy cranes to lay 84 steel belts at the bottom of the 160-foot-wide canal. Transformers equipped with backup generators will juice the metal and create a pulsing electrical field.
"What we're doing here is plugging the biggest hole. This is something that deters the fish without killing them," said Charles B. Shea, project manager for the U.S. Army Corps of Engineers. "We can't make a 100 percent guarantee, but it certainly seems unlikely any fish could swim through this barrier."
What about a human?
"You'd get a hell of a headache," Shea said.
The new electrified field, scheduled to be in full buzz by October, is modeled on a three-year-old pilot project nearby that stretches across 55 feet of canal. The existing zapper, believed to be the largest such fence in the world, relies on technology used to contain the fish in fish farms.
Researchers study its effectiveness by implanting radio transmitters in more than 100 fish swimming in the neighborhood. Each fish sends a unique signal.