It’s Fish Fry Season, and if you’re in the Midwest U.S., you might be seeing a new fish on the menu: Copi.
Well, it’s not a new fish, per se, but rather a new name for a pair of troublesome invasive species – Silver Carp (Hypophthalmicthys molitrix) and Bighead Carp (Hypophthalmicthys nobilis). When we talk about “invasive carp” in North America, we’re actually talking about a group of species that includes Silver, Bighead, Black (Mylopharyngodon piceus), and Grass Carp (Ctenopharyngodon idella). These species were introduced in the mid-20th century from Asia for use as biological control mechanisms to improve water quality and have since escaped and established populations in the Mississippi River basin (and beyond). You may also know them collectively as “Asian Carp”, but researchers and agencies now often refer to them specifically to be more accurate and reduce confusion (Kočovský et al. 2018).
As planktivores, Bighead and Silver Carp directly compete for food with native species such as Paddlefish, Bigmouth Buffalo, and Gizzard Shad (Irons et al. 2007) as well as with juveniles of many other species, thus, reducing native fish diversity and leading to decreased fish landings of more profitable native fish for commercial fishermen. One of the biggest concerns is that Bighead and Silver Carp will make it into the Great Lakes via the Illinois River and Chicago Area Waterway System, which could result in negative impacts to already stressed lake ecosystems (Robinson et al. 2021).
Because Bighead and Silver Carp are well-established throughout the Mississippi River basin, what can be done to control them? For some, the answer is, “If you can’t beat ’em, eat ’em.”
The idea of humans consuming invasive species to control them is not a new concept, with the thought being that humans can act as a “predator” – in line with the hypothesis that invasion success is due in part to a lack of enemies in the introduced range (the enemy release hypothesis, e.g., Keane & Crawley 2002). Support for gastronomic control typically comes from the fact that various animal species have been driven to near-collapse or even extinction by overharvest. Potential benefits of developing a market for invasive species beyond removing individuals and providing an economic resource include increasing awareness among the public and helping with early detection of range expansions (Nuñez et al. 2012).
But there can also be unintended consequences of creating a market to control or eradicate invasive species. Developing a market can result in pressure to maintain that species, and if the target species becomes a valuable economic resource, people may try to recreate that market in previously uninvaded regions. Human consumption also doesn’t always guarantee success if appropriate life stages are not harvested in large enough numbers from the population. It is also important to consider the spatial extent of the invasive population – if the plan is to harvest individuals to supply local customers or restaurants, it may be impractical to collect in areas with low densities or in remote areas where populations of invaders can persist (Nuñez et al. 2012).
Like all fisheries management challenges, creating a market for invasive carp involves weighing both potential positive and negative outcomes. But creating a market first involves getting people to actually … eat the invasives. Americans in general have a distaste (*ba dum tss*) for carp (Varble & Secchi 2013). Although Bighead and Silver Carp are different from the Common Carp (Cyprinus carpio, also not native to North America), and despite it being an important food source elsewhere in the world, Common Carp isn’t generally eaten in the U.S. This is in part because of the negative perception of carp as a bottom-feeder with a “muddy” taste – a social and cultural stigma that has a long history in the country (Cole 1905). In contrast to Common Carp, Silver and Bighead Carp have a mild flavor and are fast-growing filter-feeders (i.e., properties that are generally associated with being lower in contaminants).
In 2022, the Illinois Department of Natural Resources and partners announced the rebranding of invasive carp as “Copi” (pronounced “koh-pee” – short for copious). The new name is part of a broader plan to create demand for invasive carp that will help increase fishing pressure and reduce the population to hopefully help prevent their introduction to the Great Lakes.
Like eating invasive species, the idea of “rebranding” a fish species is not a new concept. Although fish provide a valuable source of animal protein for humans, some species are perceived as undesirable and have undergone “rebranding” efforts to make them sound more attractive and appetizing to consumers, and therefore easier to sell – well-known examples of fish rebranding include the Chilean Sea Bass (formerly known as Patagonian Toothfish, Dissostichus eleginoides) and Orange Roughy (formerly known as Slimehead, Hoplostethus atlanticus).
The rebranding of Copi is still getting kicked off, so it’s tough to say if it will become the new Chilean Sea Bass or Orange Roughy of the Midwest. But it’s important to remember that harvest – while another potential tool in the invasive carp management toolbox – may not be a silver bullet on its own.
Cole, L. J. (1905). The German carp in the United States. Report of the Bureau of Fisheries 1904 (pp.523–641). Washington, DC: U.S. Government Printing Office. https://spo.nmfs.noaa.gov/content/german-carp-and-its-introduction-united-states
Irons, K. S., Sass, G. G., McClelland, M. A., & Stafford, J. D. (2007). Reduced condition factor of two native fish species coincident with invasion of non‐native Asian carps in the Illinois River, USA Is this evidence for competition and reduced fitness? Journal of Fish Biology, 71, 258-273. https://doi.org/10.1111/j.1095-8649.2007.01670.x
Keane, R. M., & Crawley, M. J. (2002). Exotic plant invasions and the enemy release hypothesis. Trends in Ecology & Evolution, 17(4), 164-170. https://doi.org/10.1016/S0169-5347(02)02499-0
Kočovský, P.M., Chapman, D.C. & Qian, S. (2018), “Asian Carp” is Societally and Scientifically Problematic. Let’s Replace It. Fisheries, 43: 311-316. https://doi.org/10.1002/fsh.10087
Nuñez, M. A., Kuebbing, S., Dimarco, R. D., & Simberloff, D. (2012). Invasive species: to eat or not to eat, that is the question. Conservation Letters, 5(5), 334-341. https://doi.org/10.1111/j.1755-263X.2012.00250.x
Robinson, K. F., Alsip, P. J., Drake, A. R., Kao, Y. C., Koops, M. A., Mason, D. M., Rutherford, E.S., & Zhang, H. (2021). Reviewing uncertainty in bioenergetics and food web models to project invasion impacts: Four major Chinese carps in the Great Lakes. Journal of Great Lakes Research, 47(1), 83-95. https://doi.org/10.1016/j.jglr.2020.11.003
Varble, S., & Secchi, S. (2013). Human consumption as an invasive species management strategy. A preliminary assessment of the marketing potential of invasive Asian carp in the US. Appetite, 65, 58-67. https://doi.org/10.1016/j.appet.2013.01.022