MILFORD, Iowa | Work is complete on a temporary fence to prevent the invasive Asian and silver carp from coming into the Iowa Great Lakes. It is feared the fish, which reproduce quickly and consume large quantities of food, could crowd out native species and create ecological problems for the region.
The 45-inch-tall, 160-foot wire fence is on an outlet at Lower Gar Lake in Dickinson County. Iowa Department of Natural Resources officials hope the device will stop the fish from getting into other waterways until a more effective electronic barrier is installed.
“Our greatest fear is that these fish could impact recreation and the ecology of the lakes,” said Natural Resources Fisheries Biologist Mike Hawkins. “Ecologically, these fish are filter feeders and will compete with young fish for food.”
The carp were imported to the U.S. from Asia to clean sewage ponds and fish farming facilities in Southern states but escaped during high waters. The federal government has spent about $100 million on efforts to stop the fish from migrating from the Mississippi River system to the Great Lakes.
Local flooding last year allowed the carp to use the Little Sioux River and get past Linn Grove Dam.
Kollasch Welding and Machine and Berg Construction and Landscaping, both based in Spirit Lake, Iowa, erected the temporary fence. Kevin Vaughan, of the North Sioux City company FIMCO Industries, donated more than $15,000 for the project.
Fundraising continues for the electronic barrier, which could cost as much as $700,000. The technology emits a low-level electric shock to discourage large fish like carp from crossing into bodies of water.
Until then, Hawkins said, the temporary fence may need to be removed when water levels rise and debris clogs the system. He said the wire barrier, while not perfect, is the best option for fighting the aggressive carp.
“This has been no easy task, and we have no guarantees that the design will work effectively,” Hawkins said. “But we want to make sure we do everything possible to stop the Asian carp from moving before the installation of the permanent barrier.”
Fifty-five silver carp and 82 big head carp were found in East Lake Okoboji in March. While both species are problems for the fisheries, silver carp are more of a concern for boaters because of their tendency to grow to more than 50 pounds and jump out of the water.