The lakes, rivers, oceans, and streams on this little blue marble of ours continue to prove that they've got mysteries yet to spare.
Take, for instance, the tale of North Dakota State University grad student Alec Lackmann, who recently documented the oldest age-validated freshwater fish ever recorded, something that would make the late John Hammond very happy. Working toward a PhD in aquatic ecology, Lackmann took a trip to west-central Minnesota to study the Bigmouth Buffalo fish, a species that is native to both the United States and Canada, and is a natural counterpart to some of the most notorious invasive species in North America.
While there, he retrieved from sport bowfishers five Bigmouth Buffalo that were over 100 years old, the most ancient of which was a 112-year-old female taken at Crystal Lake (no connection to Jason Voorhees, though). That means the old girl was just a young swimmer when Teddy Roosevelt was president. They also discovered several populations almost totally comprised (85-90%) of individuals over 80 years old, suggesting long-term reproduction failure since 1930s dam construction.
Ages were determined via a combination of "thin-sectioned otoliths and bomb-radiocarbon dating," according to the official report published by Lackmann and his team in May. The results were, of course, extremely surprising, "more than quadrupling previous longevity estimates."
"The fish's age is determined by thin-sectioning the otoliths (earstones) from each fish, and then counting the annual rings on the thin section, much like aging a tree, or clam shell. We used bomb radiocarbon dating to validate that the rings we were counting in the otoliths were indeed annual. It is not normal for a fish like this to live so long," Lackmann tells SYFY WIRE. "The Bigmouth Buffalo at 112 years of age breaks the previous record by nearly 40 years. Also, Bigmouth Buffalo as a species were previously thought to live to only 26 years maximum, but the aging work on Bigmouth Buffalo was very limited and not validated prior to our work... It seems very likely there are still more 100-plus year individuals out there. However, the new and increasingly popular form of recreational sport harvest (bowfishing) is somewhat unregulated for this species — they can be taken with no limit in Minnesota and numerous other states. So these longstanding populations are being exploited at unknown and unregulated rates."
Lackmann and his colleagues worked with sport bowfishers, the commercial harvest (they are an edible species), hook-and line-anglers, and the Minnesota Department of Natural Resources to retrieve their samples. Many of the fish including the wizened, 112-year-old Buffalo were retrieved from sport bowfishers who would have otherwise discarded their take as fertilizer. Indeed, nighttime sport bowfishing has become a multimillion dollar industry in recent years, but it's rather unregulated, especially since Bigmouth Buffalo have been documented for decades as declining in certain parts of the U.S. Historically, these were one of the most populous types of freshwater fish in North America.
"The great longevity of Bigmouth Buffalo suggests a lot about this species," adds Lackmann. "They clearly are able to withstand senescence" — an overall deterioration due to age — "in ways most fishes cannot. Also, their longevity suggests they have a much slower-paced life history than previously considered, and this has implications for management. Coupling that information with the age distributions found in several populations studied, it appears this species goes through boom and bust periods of successful reproduction. In some populations, they may simply need to persist long enough to reach those boom periods."
So, could the long lifespans of these fish help us one day slow or even stop the aging process? After all, this news does come just days after the Japanese government gave the green light to human-animal gene splicing, which could make organ donor wait lists a thing of the past.
"This research has implications in several fields [like] ichthyology, aging and senescence, conservation biology. Who knows what may be discovered if Bigmouth Buffalo are studied more closely in a variety of disciplines?" finishes Lackmann.
It should be noted that Allen H. Andrews, Malcolm G. Butler, Ewelina S. Bielak-Lackmann, and Mark E. Clark are also credited for the discovery, and its eventual report.
"The Bigmouth Buffalo is capable of living and reproducing to ages that more than quadruple all previous estimates," reads the report's conclusion. "This finding serves as a prime example of discoveries overlooked and management dilemmas that can arise as a consequence of the ecological neglect of under-appreciated species."