Researchers with the Missouri Department of Conservation (MDC) have reported the first documented evidence of invasive black carp reproduction in the wild in North America.
This means big problems for native river species, according to MDC Resource Scientist Quinton Phelps.
“The finding of reproductive-capable black carp means their population will expand possibly unchecked,” Phelps said.
The finding resulted after two small unidentified carp were collected in a ditch directly connected to the Mississippi River near Cape Girardeau in November.
After genetic analysis, they were determined to be juvenile black carp and were also tested to determine their reproductive capability. Both juvenile black carp were found to be capable of reproduction. Scientists are able to determine future reproductive capability of juvenile fish through chromosome analysis.
Black carp are just one species of invasive Asian carp that are found in many rivers in Missouri. They originally arrived in the United States mistakenly in shipments of grass carp and were introduced into farm ponds first for control of parasites, then as a food fish.
When they were introduced, regulations specified they be altered so they could not reproduce. Due to flooding, and cases of accidental release in bait buckets, they’ve spread in recent decades and thrive in many rivers.
This newly confirmed information about their reproductive capability suggests there are likely more adults present in the river than biologists originally anticipated, Phelps said, which is a big problem.
Invasive species in Missouri can be detrimental to the survival of native species. For example, Asian carp compete with native fish species for food sources. They’re voracious eaters of native mussels, which are a vital species to the health of river habitat.
“Given that many of our mussel populations in the state are currently in jeopardy, additional consumption by black carp could drastically reduce their numbers,” Phelps said.
Nearly two-thirds of the 65 species of mussels found in Missouri are of conservation concern. These freshwater mussels are filter feeders, meaning they clean impurities from the water. They provide food for native muskrats, raccoons, river otters, some birds, and many native fish species.
Through their gills, mussels filter out small particles from the water and transform them into food for fish and other animals.
Black carp consumption of native mussels and competition with native species could lead to an overall poor water quality system, directly affecting humans as well as native fish.
Although this news paints a discouraging picture, Phelps said it doesn’t mean the fight is over against black carp. Instead, he said everyone can get involved in reducing their spread by avoiding accidentally introducing the species into new bodies of water when they dump bait, ensuring stocked fish come from licensed vendors, and sharing information about these practices with others.
Black carp sightings should be reported to the MDC, either by contacting a fisheries biologist at the Southeast Regional Office at (573) 290-5730, or by contacting Phelps and his colleagues at the Big Rivers and Wetlands Field Station in Jackson at (573) 243-2659.