For the first time in decades, lake sturgeons have been recorded breeding naturally in the Coosa River, a 280-mile watercourse running through the US states of Alabama and Georgia.
The discovery marks a major milestone in a long-running project to bring the ancient fish back from local extinction.
An ancient fish returns
The U.S. Fish & Wildlife Service describes the lake sturgeon (Acipenser fulvescens) as a "prehistoric species with a shark-like tail and bony plate-armoured covering". These large freshwater fish, which can grow up to two metres long and have existed since the time of the dinosaurs, were once common in the Coosa River, before pollution and overfishing wiped them out.
Their return has been the focus of a 20-year reintroduction effort by the Georgia Department of Natural Resources, which began stocking a section of the river in Georgia with juvenile fish raised from eggs brought from Wisconsin.
Now, a new study from the University of Georgia (UGA) shows clear evidence that these fish are reproducing on their own – marking a turning point in the project.
“Not only are these fish surviving, but we’re showing evidence that they are capable of reproducing and that the young are able to survive on their own,” says Martin Hamel, lead author of the study and associate professor at UGA’s Warnell School of Forestry and Natural Resources.
How do scientists know the fish are breeding?
Because lake sturgeons take years to mature – 13 to 15 for males and even longer for females – confirming whether they were breeding in the wild has been a challenge. Annual stocking also made it hard to tell if any juveniles found were the result of natural spawning.
However, in 2020, the COVID-19 pandemic brought a pause to stocking. When researchers sampled fish in 2022 and 2023, they found individuals that could only have hatched in the wild during that year.
“That was kind of the smoking gun for confirming that these fish were reproducing in the wild on their own, which really is a huge benchmark for recovery,” says Hamel. “It doesn’t necessarily mean that the population has recovered, but it’s definitely a step in the right direction.”
The research team will continue monitoring the population to see if this natural reproduction continues. For Hamel and his colleagues, the lake sturgeon represents more than just a species. “They’re really kind of a charismatic, unique fish, and they’ve been around for a really long time,” says Hamel. “They’re an integral part of the aquatic ecosystem.”
Top image: Coosa River, Georgia. Credit: Getty
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