DECATUR — Commercial fishermen are removing thousands of Asian carp from Lake Decatur dam, using a net that stretches 800 yards to scoop up the non-native species.
The fishermen, contracted by the state Department of Natural Resources, started their work Monday. It’s unclear how long the process will take, but once the carp have been removed, they will be taken by semitrucks to a company in Bushnell, Illinois, that will use them to create fish meal and fish oil.
The unusually large gathering of fish was reported to the state last week. Kevin Irons, DNR aquaculture and aquatic nuisance species program manager, said it is difficult to estimate how many are outside of the dam, but it appears to be anywhere from 50,000 to 150,000 pounds of fish.
“We've seen some really big fish here,” Irons said. “Some are nearly 20 to 30 pounds.”
Asian carp are an invasive species, meaning they can cause serious damage in lakes and rivers by out-competing native fish populations for food and space. They were brought to the United States in the 1960s and 1970s to control algae, weed and parasite growth in aquatic farms. They escaped into the Mississippi River and have been spreading ever since, changing the ecology of bodies of water wherever they take root. Some species are also known for jumping high out of the water, which can cause injury to boaters and other recreational lake users.
The dam was turned off for a short time Monday morning in an effort to draw out as many of the fish as possible while fishermen sailed along the perimeter of rocks near the dam. They used a 30-foot deep seine net, which is designed to catch fish like Asian carp. Irons said the fishermen try not to remove native species along with the invasive carp.
"We are still working out what to do with the fish stuck between the dam and the rocks, but the priority is getting these fish from behind the rocks and in the river, out," Irons said.
There are four species of carp that, together, are commonly called “Asian carp,” according to the National Park Service. They are bighead carp, black carp, grass carp and silver carp. Irons said the fish spotted in Lake Decatur so far appear to be silver carp, which feed almost continuously on plankton and can leap as high as 10 feet out of the water, and black carp, which eat mussels and snails and have teeth similar to human molars.
The city of Decatur has already taken steps to prevent the fish from making it into Lake Decatur. Five years ago, a 4-foot screen was installed on top of the dam to prevent the fish from jumping over when the water is high.
Joe Nihiser, the city’s lake maintenance supervisor, said removing the fish is challenging because it is the first time the city has had to take such measures.
"We are in similar spots to the rest of Illinois, it seems, as they are facing the same problems with the Asian carp," Nihiser said. "Thankfully, it is not as bad in Decatur."
Irons said the commercial fishermen have been sent out to the Illinois River recently to use the exact same deployment process for the carp.
Great Lakes regional leaders are set to meet this week in Chicago to discuss a plan devised by the U.S. Army Corps of Engineers to keep the fish from invading Lake Michigan by strengthening a dam near Joliet.
Earlier this month, leaders of states and Canadian provinces in the region urged Congress to allocate money for the plan, which would cost $778 million.
Nihiser said there is not an immediate concern for the dam on Lake Decatur, mainly because the water is not too high. But the city is thankful for the state’s assistance in removing the threat.
"We are grateful to have the help from DNR in keeping the Lake Decatur ecosystem on the right track," Nihiser said.