State and federal wildlife officials plan to pull out all the stops this month to eliminate Asian carp from Creve Coeur Lake in St. Louis County.
The invasive species are relentless bottom feeders that have damaged water quality, disrupted the food chain and driven down native fish populations in many Midwestern waterways.
St. Louis County Parks is working with the Missouri Department of Conservation, the U.S. Geological Survey and a number of other agencies to implement a tactic to remove Asian carp from the lake. The "unified method," involves using nets and electric barriers to create a grid-like system in the lake. The method has seen some success in China and Illinois.
"It's sort of like creating a big plastic comb with nets that would move from one end to another, actively pushing and herding the fish out of a section of lake and placing nets across to not allow them access to the area you just cleared," said Kevin Meneau, a fisheries management biologist at the Missouri Department of Conservation.
Simply netting the fish has not been effective, he added.
"All of the traditional techniques that we use on native fishes don't work with Asian carp," Meneau said. "Their jumping ability tends to get them over nets that we traditionally use."
Originally brought over from Asia in the 1960s for aquaculture, Asian carp have entered bodies of water in Missouri and Illinois, mainly due to flooding. Missouri wildlife officials estimate the species first arrived at Creve Coeur Lake prior to 2009, likely due to flooding from the Missouri River.
In addition to hurting the lake's crappie population, a draw for recreational fishermen, the Asian carp's jumping behavior also pose a hazard to people who navigate on the lake.
"We have to [remove them] when it's cold outside otherwise the fish will jump more," said Duane Chapman, who leads Asian carp research at the U.S. Geological Survey.
Chapman had deployed the unified method in Morris, Illinois, and said the technique was able to remove about 70 percent of the Asian carp in the area. However, it requires a lot of coordination and "moving parts."
Meneau added that it would be costly.
"This method's going to take, on any given day, eight to 12 boats, thousands of feet of net and a custom-made live capture net, which we've never used before and is still being made," Meneau said.
The Asian carp that are taken from the lake will likely be disposed in a sanitary landfill, Meneau said. If the unified method is effective, the crappie fishery could recover in three to five years.
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