The Black Carp, one of four invasive species in North America, has made it into the Mississippi River Basin.
A new multi-year report from the US Geological Survey (USGS) found that the range of Black Carp in the Mississippi River Basin now includes the entire Mississippi River between New Orleans and the southeastern edge of Iowa, near Keokuk.
The Black Carp is a large species of fish endemic to parts of East Asia, typically growing over three feet in length and weighing over 100 pounds. The fish was intentionally brought to the states during the 1970s as a means of pest control for water snails in fish ponds. The population grew rapidly out of control.
The research was conducted by analyzing the “ear stones” or “otoliths” – of more than 200 Black Carp from 2011 to 2018 to distinguish whether they were wild or farmed.
Patrick Kroboth is a vibiologist at USGS’s Columbia Environmental Research Center in Columbia, Missouri and one of the authors of the study, published in Biological invasions. He said that the carp’s ear stones, among other methods, figured prominently in their findings.
“As a fish grows,” Kroboth explained, “that calcified structure deposits the microchemistry of the water around that fish—the environment it lives in, it’s caught there.”
While the presence of the Black Carp in part of the Mississippi River Basin has been previously reported, the research concludes that the population is now self-sustaining.
The Black Carp is a mollusk, which means that it mainly eats snails, clams and mussels, among other molluscs. Kroboth said that poses risks to the Mississippi River and its tributaries.
“Many of North America’s mussel species are threatened and endangered,” he said. “It’s obviously a concern.”
Credit: USGS. https://www.usgs.gov/media/images/wild-black-carp
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Back in 2003, the first non-captive Black Carp was identified in a southern Illinois oxbow lake adjacent to the Mississippi River. Commercial fishermen in Louisiana previously reported catching the fish throughout the 1990s in the Red and Atchafalaya rivers.
Brad Parsons, with the Mississippi Interstate Cooperative Resource Association, said that biologists have long suspected that black carp live in the basin, and now the priority must be to figure out how to manage the pest.
“The fact is — fish don’t understand political boundaries, and they’re not bound by them,” Parsons said. “A fish that’s in the Mississippi River one day can be in the Ohio River the next day.”
https://www.usgs.gov/media/images/black-carp-observations-mississippi-river-basin
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Besides the main stem of the Mississippi River, the Black Carp’s range also includes the majority of its tributaries: the Cumberland, Illinois, Kaskaskia, Missouri, Ohio, Tennessee, Wabash and White rivers.
Parsons said that managing invasive species in the Mississippi River will require a collaborative and multi-faceted approach to effectively curb the existential threat posed by the carp.
“Our native species are incredibly resilient. They’ve been here a long time,” Parson said. “But they’re facing a full-frontal assault. And, you know, we don’t need more new challenges to be thrown into the mix here.”