The invasive black carp has officially established a population in the Mississippi River, which has officials scrambling to find ways to curb the havoc the fish is continuing to wreck on the fragile ecosystem.
A study co-authored by members of the U.S. Geological Survey (USGS) and published in the journal Biological Invasions found that the Asia-native species is naturally breeding and living through adulthood in the river.
“This is the most comprehensive study and the first research to provide strong evidence that they are present and sustaining on their own,” said one author, Patrick Kroboth, a research fish biologist with the USGS in a USGS statement.
“…the population primarily consists of fertile fish that are capable of reproducing,” he continued. “This suggests that the environment has suitable conditions for black carp’s entire life cycle.”
Black carp, which are also known as Chinese black roach, are native to rivers throughout Vietnam and China. The U.S. government first recorded them in the states in the 1970s. The fish accidentally made it overseas in stocks of grass carp that officials had been intentionally importing for decades.
Some black carp also came over to help control yellow grubs that were spreading in aquaculture ponds. Between pond flooding and the stowaways, the species was able to spread populate over the decades.
Scientists are Developing a Population Control Method that Will Make Reproduction Difficult
Unfortunately, the fish have been devastating the Mississippi River basin. They live on endangered mussels and snails, which are important for algae control. And because they can grow to be five feet long, they have to eat a lot of those native creatures to survive.
Officials deemed black carp invasive in 2007 and banned their import under the Lacy Act. Following the decision, biologists have been fruitlessly trying to slow population growth. Methods have included walls of bubbles, netting, explosions, chemical culls, and noise.
So far nothing has actually helped reduce the black carp population, but they have been successful in preventing the fish from spreading to other waterways. Some of the chemical attempts showed signs of progress, but they also killed native fish. So officials banned them.
Currently, scientists are working on new developments that could stop black carp from reproducing. But while they finalize that plan, they’re asking people to get out there and help by catching and eating the carp. And they also want everyone who catches the invasive species in the wild to report it to the USGS Nonindigenous Aquatic Species database. That way, they can better gauge the situation.