EUREKA — They all will die.
That's the plan for the overpopulated European carp community in Eureka Lake when the city of Eureka and the Illinois Department of Natural Resources team up this summer to mostly empty and ultimately bring its game fish habitat back into balance.
"Starting the fish population from scratch will regain the health of the lake," Eureka administrator Melissa Brown said Friday. "Hopefully we will have a new and improved lake by early spring."
Thousands of largemouth bass, bluegill and channel catfish were killed in the harsh winter of 2013-14 because of low oxygen levels in Eureka Lake that common carp, or European carp, were easily able to survive, according to Rob Hilsabeck, fish biologist with IDNR. The death of nearly all the game fish allowed the remaining carp do what carp do best — breed like crazy — and effectively take over the 30-acre lake.
"The reproduction potential of a large brood carp is as many as two million eggs and can be produced in low oxygen conditions," Hilsabeck said Friday. "(The carp) were able to get an unlimited spawn in 2014."
The only way to clear a lake of carp so that game fish can be reintroduced and thrive, is to kill them all and start from scratch.
So, the city will pull the plug, so to speak, and drain the lake in August, leaving a two-to-five acre mud puddle in the middle of the lake. A root-based compound that kills only fish, called rotenone, will be sprayed into the shallow mud puddle by IDNR, killing all the carp in a matter of days. The carp will be left to decompose where they die and the lake will refill naturally, and slowly, over time with rainwater and runoff.
"Dead fish go rancid pretty fast so there will be a stench," Hilsabeck said. "The lake is going to smell a lot more like a river than a nice pristine lake for a time."
Baby game fish from IDNR hatcheries will be introduced into the lake in the spring. IDNR will allow the lake to be fished in 2019 and 2020, but fish will probably not have grown to a harvestable size in that time.
"It will be mainly catch-and-release the first two years," Hilsabeck said. "By 2021 the largemouth bass and the bluegill should be big enough to keep."
The drawdown of the lake is necessary to save money, otherwise trying kill all of the carp in a lake that is full would require more rotenone than is economically feasible. The city has budgeted $20,000 for the project, but hopes to only need to spend about $10,000, Brown said.
Hilsabeck was on the lake Friday stunning the few surviving game fish with electric shocks to be netted and relocated to Bowen Lake in Washington.
"We got about 75 largemouth bass," Hilsabeck
The city will hold an information meeting for the public about the drawdown of Eureka Lake on June 19 at the lake Pavilion, 203 Lake Road, from 6:30-7:30 p.m. IDNR's Hilsabeck and city representatives will be on hand to answer questions. In the interest of time, those with questions are asked to submit them by email in advance to administrator Brown at email@example.com.
Scott Hilyard can be reached at 686-3244 or by email at firstname.lastname@example.org. Follow @scotthilyard on Twitter.