Joe Deters took a frozen, 11-pound silver carp and cut it with a bone saw before dropping it, piece by piece, into the small meat grinder.
The “grinding room” at the Columbia Environmental Research Center, an arm of the U.S. Geological Survey on New Haven Road, has become a stepping stone for a potential solution to an environmental problem in the Missouri River and other inland waterways by turning unwanted fish into food for zoo animals.
Deters, a biologist in Columbia for the U.S. Geological Survey, was grinding the fish on Tuesday for MU food scientist Andrew Clarke, who has been working for a year to develop “carp cakes.”
The hope is that the cakes will become popular enough to create a market for the invasive species and take a bite out of their increasing numbers.
Two invasive species — silver and bighead carp — continue to pose ecological and safety issues in the Missouri River. As the two species of the so-called Asian carp grow, they reach a size in which they become immune to native predators. Often growing to 10 to 12 pounds, they can pose a danger to boaters. The rumble of a motor can cause the carp to propel themselves out of the water with considerable force.
Duane Chapman, a research fish biologist with the Geological Survey, said the invasive carp “are still at high abundance in the river and will be in the foreseeable future. But given the right tools, we will be able to control this thing in 10 years and have a market for these fish.”
Clarke has been working with Chapman and Ellen Dierenfeld, a nutritionist at the St. Louis Zoo.
“It was a dream a year ago, and now it’s starting to develop into a product,” Chapman said. “We’re getting closer.”
While the cakes are being developed and experimented with locally, Chapman’s hope is that a commercial fishery or private investor will take the business on. Chapman said Schafer Fisheries in Illinois has volunteered to grind the next batch. He’s also in talks with a commercial fishery in Florida.
Chapman is working to get a more accurate measure of the carp population to encourage investments in a potential market.
“My vision is to develop a model that will tell us how many fish are in the river and how many there will be if we harvest a certain number of fish,” Chapman said. “To get entrepreneurs to invest in this situation, we need to know how many fish there are out there.”
While smaller batches of carp cakes have been developed successfully, Chapman and Clarke are now working to develop larger batches, closer to the size of what a commercial fishery might produce, to determine whether changes need to be made.
“After these industrial-sized batches are successful, then we will be feeding them to the zoo animals,” Chapman said.
Clarke forms the cakes by using a process called cold-set binding. Clarke also adds FDA-approved food ingredients but said he doesn’t yet have a set recipe.
“There are an awful lot of angles to this,” Clarke said, “The nutritional needs of animals change, and we’re trying to understand what we’re giving them.”
Ellen Dierenfeld, nutritionist at the St. Louis Zoo, has been speaking with the Lincoln Park Zoo, Shedd Aquarium and Sea World about joining in an upcoming pilot study.
“We’re going to be looking at animal response, acceptability of the product, and the health issues and economics of it,” Dierenfeld said. “We are still actively pursuing all of the angles, but it’s slower going than we want it.”
Despite the slow progress, Chapman and Clarke are already looking beyond a market for zoo animals.
“We’ll look at this for pet foods after the zoos are taken care of,” Chapman said. “We’re trying to develop a process that will truly develop a market.”