Biologists were studying fish in the Great Lakes and discovered that some may have been alive when Galileo first pointed a telescope at Jupiter, lurking as armored giants older than the United States itself

In the early 17th century, when Galileo was training his telescope on Jupiter’s moons, certain fish may have already been gliding through the cold depths of the Great Lakes. Today, those same waters may still hold them.

A new study suggests that lake sturgeon — armored, ancient, and capable of reaching lengths beyond five feet — could live far longer than anyone previously suspected, potentially outliving not just individual humans, but entire civilizations built above them.

A fish older than the United States — by centuries

Published in the Journal of Fish Biology, new research concludes that male lake sturgeon may live up to 435 years — nearly three times the age of the previously known record-holder. That record was set by a single fish caught in 1953 near the Minnesota-Canada border, estimated at 154 years old. The new findings don’t just nudge that number upward. They suggest the old record may have been a dramatic undercount.

Lake sturgeon are already remarkable by any measure. Their ancestors swam alongside dinosaurs roughly 200 million years ago. Today they’re the largest fish in the Great Lakes, typically reaching four to six feet long and weighing between 30 and 80 pounds. Their known average lifespan sits at 50 to 100 years — an estimate that may now be obsolete.

“All sturgeon species now need to be reassessed for their age because of this paper,” said ichthyologist Prosanta Chakrabarty of Louisiana State University, who wasn’t involved in the research.

Why counting rings on scales isn’t enough

Aging a fish usually means counting annual growth rings — called annuli — on its scales or fin spines, much like counting rings on a tree trunk. For fast-growing, shorter-lived species, this works well. For lake sturgeon, it breaks down entirely.

In slow-growing, long-lived sturgeons, the rings eventually compress, merge, and become indistinguishable from one another. Sometimes they stop forming altogether. The standard method hits a wall — and that wall may be far short of the fish’s actual age.

To work around this, researchers drew on 44 years of data collected between 1980 and 2024, tracking thousands of sturgeon across five Upper Great Lakes waterways: Black Lake, the Sturgeon River, the Menominee River, the St. Clair River, and Lake Winnebago. The method they used is called capture-mark-recapture. Researchers caught sturgeon, recorded their sex and length, and implanted microchip transponders — the same technology used to identify lost pets — just under the skin. Released fish, if caught again years later, were re-measured and released again, building a detailed growth record over time.

How the age estimates were built — and what they found

From those growth records, the team calculated average annual growth rates for each population, accounting for differences between sexes and waterways. The variation was striking. Sturgeon in the Black River grew less than 40% as much per year as those in the St. Clair River — a gap that shows how profoundly environment shapes these animals’ lives.

Using those rates, researchers developed equations to estimate the age of sturgeon at their approximate maximum lengths: about 5’3″ for males and 5’11” for females. Median predicted ages at those lengths ranged from 87 to 215 years for males and 90 to 248 years for females. Then came the outliers — some larger individuals had predicted median ages reaching 435 years for males and 292 years for females.

Study co-author Edward Baker, a fisheries researcher at the Michigan Department of Natural Resources, noted that even these figures may not represent the upper limit. Larger, older fish could still be out there. One proposed explanation for such longevity is winter torpor: during cold months, sturgeon enter a state of dramatically reduced metabolism, heart rate, and respiration — a physiological slowdown the researchers suggest may extend their lives significantly.

Caveats: what scientists still need to verify

Not everyone is ready to crown the lake sturgeon as a record-breaker just yet. Outside experts describe the capture-mark-recapture method as well-established but less precise than radiocarbon dating — the technique used a decade ago to confirm that Greenland sharks can live for centuries.

Chakrabarty compared the growth-based approach to “measuring your kids’ height over time on a wall and predicting how tall they will be when they stop growing.” Informative, but still an estimate. That said, the same method correctly predicted Greenland shark longevity before radiocarbon dating confirmed it — which matters.

Baker says they’ve reached out to the scientists behind the Greenland shark radiocarbon work to explore a similar verification effort for sturgeon. Until that confirmation arrives, scientists are urging caution. Calling lake sturgeon the oldest freshwater fish on record should wait for harder evidence.

A conservation crisis hiding in slow motion

The longevity findings land against a sobering backdrop. An estimated 15 million lake sturgeon once lived in the Great Lakes. That population has since fallen to less than 1% of its historic figure, decimated by unregulated harvesting in the late 19th and early 20th centuries.

Recovery is painfully slow by design. Females don’t reach sexual maturity until 20 to 25 years of age, and once mature, they may spawn only once every four to nine years. A species that reproduces this infrequently can’t simply bounce back from collapse.

The new research makes the situation more urgent. If some living sturgeon survived the mass slaughter of centuries past, the species’ population turnover is far slower than existing conservation models have assumed — meaning management strategies built on shorter timelines may be miscalibrated. Experts are calling for strict harvest limits and revised plans. “We need to protect the species from harvest,” Baker said, “or at least be very restrictive in how much harvest is allowed, to give populations the opportunity to recover.”

Radiocarbon verification, if it proceeds, could settle the age question definitively. For a fish that may have been alive before the United States existed, the science is only just beginning to catch up.

Learn more about the discovery here: Baker, E. A., Colborne, S. F., Auer, N. A., Scribner, K. T., Larson, D. L., Briggs, A. S., … & Donofrio, M. C. (2026). Lake sturgeon (Acipenser fulvescens) growth and longevity estimated from adult capture–mark–recapture data. Journal of fish biology.