MILFORD, Iowa (AP) — A nearly $1-million electronic fish barrier has succeeded in stopping invasive Asian carp from the Iowa Great Lakes, officials said.

The fish first swam into the lakes during flooding in 2011, the Sioux City Journal reported. They had previously been kept out by dams on the Little Sioux River in Harrison County and near Linn Grove.

The Asian carp species are thought to be a major threat to native aquatic species throughout the Midwest. One species, the silver carp, poses a safety hazard because they leap from the water when startled.

In 2011, commercial fishermen netted 82 bighead fish and 55 silver carp in East Lake Okoboji. Officials feared the fish would reproduce quickly, which would damage the bodies of water and threaten the $300-million tourism industry at the Iowa Great Lakes and Dickinson County.

The fish weren't a welcome sight in local bait shops.

Tammy Wittkamp of Stan's Bait Shop in Milford recalled sarcastically thinking, “Oh, well, that would be perfect.”

“We really need them in our life,” Wittkamp said. “One more thing.”

The 21-foot-long fish barrier was built in 2012, and it has eight electrodes installed that emit an energy pulse, killing any fish that attempts to swim through.

Officials believe the blockade is working. There have been few reports of Asian carp being netted or sighted.

“We think we closed the barn door before we got too many of them,” said Phil Petersen, of the Iowa Great Lakes Alliance.

Lakes Area fishing guide John Grover said he has not spotted any Asian carp.

“I've never heard of anybody seeing one and I'm out here eight hours a day every day,” Grover said.

The battle against Asian carp in the Iowa Great Lakes appears to be one of the few times officials are ahead on prevention of invasive fish species, said Mike Hawkins, a fisheries biologist with the Iowa Department of Natural Resources.

“We got the upper hand quickly,” Hawkins said. “A lot of times there are losing battles.”

In South Dakota, wildlife officials will kill every fish next month in Lake Yankton, which was overrun by Asian carp and other undesirable fish by the 2011 flooding.

Hawkins said even though it appears that officials have won the upper hand against Asian carp in Iowa, they will be closely monitoring for signs of dirty water, disappearing vegetation and sport fish species.

“It's always shades of gray. It's never black and white,” Hawkins said. “We want to really monitor the situation.”


Information from: Sioux City Journal,