Research Revelations—Recent research at North Dakota State University (NDSU) has proven that bigmouth buffalo, a species native to North America, can live more than eight decades longer than previously thought.* The research team, led by Alec Lackmann, doctoral graduate research assistant in the NDSU Department of Biological Sciences, recently published their work about aging the fish.
The researchers used thin sections of otoliths, ear stones that lay down layers as fish age and form annular marks, collected from bigmouth buffalo from 12 populations in Minnesota. They validated ages using bomb radiocarbon dating, which tests for 14C carbon isotope produced by thermonuclear bomb testing in the 1950s and 1960s. The radiocarbon dating method shows time-specific markers in otoliths.
Using these methods, they found bigmouth buffalo can reach 112 years of age, which more than quadruples previously known longevity estimates, and makes it the oldest known freshwater teleost (a group of about 12,000 fish species). They report that prior to their findings on bigmouth buffalo, the oldest ages for freshwater teleosts were reported to be 73 years for freshwater drum and 62 years for arctic lake trout. Sturgeon, gar, paddlefish, and bowfin are taxonomically categorized in groups other than teleosts, and lake sturgeon are believed to live up to 150 years old.
Nearly 400 fish were aged in the study with five exceeding 100 years old. Nearly 200 fish were aged in their 80s or 90s. The researchers found many populations of bigmouth buffalo had 85 to 90 percent of the population comprised of individuals more than 80 years old, suggesting recruitment failure since dam construction the 1930s.
The researchers suggest that in light of the species’ revised life history, bigmouth buffalo require urgent attention. Dams are cited as a cause of recruitment failure for bigmouth buffalo because they can restrict access to spawning habitats and disrupt environmental signals that cue spawning. A further threat in Minnesota, they point out, is increased angling pressure since 2010, when nighttime bowfishing with artificial lights became legal. They conclude that the new life history evidence “points to a precautionary approach to the conservation of buffalo fishes in general,” in addition to other species with similar life-history traits.
*North Dakota State University. (2019, May 30). NDSU research proves area fish species lives beyond 100 years [Press release, https://www.ndsu.edu/news/view/detail/37752].
**Lackmann, A. R., A. H. Andrews, M. C. Butler, E. S. Bielak-Lackmann, and M. E. Clark. Bigmouth buffalo Ictobus cyprinellus sets freshwater teleost record as improved age analysis reveals centenarian longevity. Communications Biology | (2019)2:197 | https://doi.org/10.1038/s42003-019-0452-0 | www.nature.com/commsbio.