A science team uncovered a remarkable population in a desert lake in Arizona, United States, revealing some of the oldest living animals on the planet. The find matters because it marks a second instance where an animal genus is shared by three or more species. These creatures show life expectancies surpassing a century, and the discovery could spark new avenues in aging research and the possibility of extending human longevity.
The study centers on three species within the genus Ichthyopus, commonly known as buffalo fish.
According to the study’s lead author, Alec Lackmann, a glaciologist and professor at the University of Minnesota Duluth, the findings unlock a wealth of knowledge about aging, longevity, and late life within this lineage. He stated that the work sheds light on phrasing potential and invites closer inquiries into how vertebrates age, including humans. The big question he poses: what is the buffalo fish’s fountain of youth?
How was age determined?
Previously, Lackmann studied buffalo fish and his 2019 work showed that the maximum age for largemouth buffalo could exceed 100 years, far beyond the earlier estimate of around 25 years. A more refined aging method was used this time. Rather than examining scales, otoliths or ear stones from inside the fish skull are prepared in thin sections to reveal age. Lackmann explained that these stones accumulate yearly layers, and when viewed under a microscope, the number of layers corresponds to the fish’s age.
Otoliths appear in roughly 97 percent of fish species. These small, stone-like structures continually grow, forming a new layer each year. When processed correctly, scientists can count the layers, much like tree rings, to determine the fish’s age.
Buffalo fish are native to central North America, including Minnesota, but the specimens in this study were found in Apache Lake, a reservoir in the desert southwest. Originating from breeding ponds along the Mississippi River, buffalo fish were introduced to Roosevelt Lake in Arizona by government programs in 1918. While Roosevelt Lake has seen commercial fishing, populations in Apache Lake have remained relatively stable.
When catch-and-release anglers noticed distinct orange and black markings on many of the fish, they sought to learn more about these patterns and reached out to Lackmann. A fisherman from Arizona contacted the scientist and invited him to a fishing day at Apache Lake, where collected samples would be donated to science.
More than 100 years
By examining collected fish and analyzing otolith ages, Lackmann found that some buffalo fish from the 1918 population in Arizona are likely still alive today. He also noted that most buffalo fish in Apache Lake hatched in the early 1920s, and more importantly, three distinct buffalo species inhabited the lake. They were all over a century old, a longevity record not seen in many freshwater fish species elsewhere in the world.
According to Lackmann, this discovery opens up broad possibilities for future work on this unique group. The long lifespans present a golden opportunity to study genetic and physiological factors, disease resistance, and aging across ages. He suggested that Ichthyopus could become a valuable focus for gerontology research, potentially turning Apache Lake into a hub for diverse scientific explorations in the years ahead.
Reference work: Nature, 2023, s41598-023-44328-8, Figure 1 (attribution following publication)
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The findings are cited with the support of environmental researchers and ongoing conservation efforts, highlighting how long-lived freshwater fish can inform aging science. The study underscores the importance of preserving habitats like Apache Lake and supporting ongoing field research to expand understanding of vertebrate aging across species and environments.
Notes and acknowledgments were provided by the involved teams and institutions, with observations published to share insights with the broader scientific community.
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