Seeking Grand Solutions

By Gilbert Randolph | July 1, 2024
From Missouri Conservationist: July 2024
Asian Carp Removal
Seeking Grand Solutions

In September, MDC collaborated with FKF Fisheries, Kansas Parks and Wildlife, and the U.S. Fish and Wildlife Service (USFWS) to remove 38,700 pounds of invasive carp from the Grand River on portions of water near Brunswick and Bosworth. The effort was the second removal in the Grand River and an opportunity to test experimental methods of removing these destructive invasive species, to quantify how many fish need to be removed to lower their populations, and to begin making connections to find a use for the fish once they are harvested.


Silver and bighead carp were introduced in the 1970s for their ability to remove algae from aquaculture systems and sewage treatment plants, but they escaped and quickly began to reproduce in the basins of the Mississippi and Missouri rivers. They have now been found in 20 states and pose a serious threat to the balance of aquatic ecosystems around the U.S.

According to USFWS, they are native to the Amur River of northeast Asia. While they are threatened in their native range, they have found tremendous reproductive success in our own river systems. They are also an important food fish for much of the world and, according to the 2022 U.N. Report on the State of World Fisheries and Aquaculture, silver and bighead carp rank in the top six most farmed fish in the world. Sometimes backed by government subsidies in Illinois and other states, these fish are being exported to overseas food markets.

Bighead and silver carp are invasive nonnative species that serve no beneficial purpose to Missouri’s ecosystem. Found in large rivers and lakes across Missouri, bighead and silver carp can outcompete native plankton-eating fish, including paddlefish, bigmouth buffalo, and the young of many other desirable native fishes. Both species are large, heavy-bodied fish, but here are just a few characteristics that distinguish a bighead carp from a silver carp:

  • A bighead’s eyes sit lower on the head.
  • A bighead carp’s head is larger than that of a silver carp.
  • A bighead carp’s body is covered with dark splotches.

Researching Removal

With grant funding from USFWS, MDC has been researching better methods of removal and gathering data on how much harvest is needed to put a dent in their populations. The majority of the roughly 1.5 million dollars earmarked for carp control by USFWS has historically been focused on keeping silver and bighead carp out of the Great Lakes. It is feared that the introduction of these fish into the Great Lakes would cause economic and ecological devastation. For similar reasons, the Mississippi Interstate Cooperative Resource Association, state agencies, and other partners have been making the case for allocating funding for carp removal in other parts of our big rivers as well.

There are numerous barriers to overcome in tackling how to control these invasive species, a need for more data on catch methods being one such challenge.

According to Kasey Whiteman, MDC resource science field station supervisor, most of the invasive carp harvested in Missouri is in the central part of the state on the Mississippi River. Since the Mississippi River has had more funding and subsidies, there’s more participation from commercial fishermen and the larger, slower sections of water is easier to fish than other systems such as the Missouri River.

Both silver and bighead carp are pelagic fish, swimming in schools in the upper part of the water column. They are difficult to stun and, especially in the case of silver carp, will jump out of the water to escape the effects of electrofishing gear or nets. Some wildlife managers have found success using this behavior to corral large schools of fish using motor noise or electrofishing, but in the Grand River removals, several promising new methods were put to the test.

Testing Removal Methods

The first of these new boat setups is a “dozer trawl.” This is a boat that uses a combination of electrodes hung from the front of the boat and a net that is dragged below the front of the boat to collect the stunned fish. This method found success in shallower water if there weren’t a lot of snags.

The second experimental method is a “paupier boat,” which uses two nets hung from the side of the boat as well as electrofishing gear hung from the front of the boat to stun the carp and catch them. This method was most effective in deeper bodies of water.

Gill nets and traditional electrofishing were also tested in this removal, with the gill nets being more effective in deeper water, while the traditional electrofishing excelled in shallow water where heavy snags would make it difficult to use catch methods that rely on large nets.

The first of these removal events closed off a 6-mile stretch of the river using nets. Limiting the movement of fish made it possible to estimate how much of the total population of invasive carp was removed. The total came out to 24,500 pounds of invasive carp removed, which equaled approximately 50–60 percent of the carp population in that closed section of river.

The second event covered 9 river miles and unlike the first removal, the river was not blocked with nets to prevent fish from moving down or upstream. After eight netting sessions, 38,700 pounds of carp were removed from the system. The percentage of these fish as a part of the biomass in the river is still being calculated.

Only 8 percent of the fish caught were native fish. The team was able to set their gear to target the upper water column and largely avoid catching non-target species. Keeping bycatch low will be a critical aspect of creating methods for removing the carp without negatively affecting the desirable native fish in the river.

Using the Fish

Once the fish are caught, there is the question of what to do with them.

“The invasive carp removed by commercial fishermen are utilized in multiple ways, such as food products, fertilizer, fish oil, fish meal, and bait,” Whiteman said.

Illinois has created the “Copi” program, which is a renaming effort that both seeks to connect American consumers with the culinary merits of bighead and silver carp while also providing opportunity for commercial fishers to sell directly to restaurants and processors. The restaurants included on the Copi website span everything from classic midwestern style po’boy sandwiches to the Japanese street food okonomiyaki.

Whiteman noted that the fish caught in the Grand River tended to be in the 3-to-5-pound range, which is a smaller size than what is typically desired for food production. There may be potential in other river systems in Missouri to catch fish that are food market sized, and there have been efforts to demystify how to prepare silver and bighead carp so they can start becoming more accepted as a food source in the U.S.

Besides a food product, silver and bighead carp can be used in the commercial bait market. Much of what was caught in these removal projects will be sold as cut bait for anglers or as bait for lobster and crayfish fishermen. This use holds some exciting promise as an alternative to bait species such as herring and menhaden, which have faced challenges regarding overharvest.

INVERSA Leathers, a company that specializes in creating leather products from invasive species, has developed a product from the skin of captured fish. Several major brands are currently testing products for their application in the fashion industry.

Henri Ferre of INVERSA Leathers stressed the importance of developing supply chains for these fish to help establish a commercially viable system of harvest.

“Some states have limited their incentive programs to just pay reimbursing processors or harvesters, but we believe there is a lot of room to expand and improve upon the commercial harvest within Missouri and other states by building out the local supply chain with other valuable products,” Ferre said. “We’ve done this with lionfish, we’ve done this with python. We’ve started to implement our model in Mississippi and are exploring other lower basin states. We think our model could be replicated across the basin and facilitate large-scale removals of carp.”

Like any fishery, there is no one-size-fits-all solution, and a multiplicity of partners are needed to create a future for commercial carp harvest in the U.S. The current MDC efforts to research invasive carp control will need more dedicated funding and partnerships in the commercial fishing industry to help create reliable methods of harvest, measurable harvest goals, and markets for the fish once they are caught. 

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