The bigmouth buffalo, a North American species of freshwater fish, can live for more than 100 years – that’s over 80 years longer than previously thought. The fish has now been crowned the longest-lived freshwater teleost (a vast group of bony fishes) and the oldest age-validated freshwater fish on the planet.
Until now, the bigmouth buffalo (Ictiobus cyprinellus) was thought to live to about 26 years of age. That was according to a 1999 study based on fish found in Oklahoma. The team behind the new study, published in Communications Biology, turned to Minnesota’s bigmouth buffalofish (the city of Buffalo in Minnesota is named after the species) and determined their ages using bomb radiocarbon dating.
This involved looking at levels of carbon-14 in the fish’s otoliths, tiny structures found in the inner ear that continue to grow throughout the fish’s life. Levels of carbon-14 can be used to determine age thanks to the atomic bomb tests carried out in the mid-20th century. These tests massively increased the amount of this radioactive isotope in our environment before it declined once more to pre-bomb test levels.
The researchers, led by North Dakota State University, looked at almost 400 fish and found that five were older than 100 years of age. The oldest bigmouth buffalo was 112, while nearly 200 fish were in their 80s or 90s. The fact that so many of the fish studied were very old (85-90 percent were over 80 in multiple populations) suggests that the species has had little success reproducing for many decades. The study authors note that this is likely due to the construction of dams during the 1930s.
The largest of the buffalofish, the bigmouth buffalo can grow to an impressive 1.2 meters (4 feet) in length and weigh as much as 29 kilograms (65 pounds). The species is very important to the health of the local ecosystem because it competes with invasive species like the silver carp and bighead carp for resources, keeping these creatures in check. Bigmouth buffalofish also eat invasive zebra mussels in their larval stages, providing an important ecological service as these shellfish cause economic and ecological damage and affect swimmers and boats.
Unfortunately, bigmouth buffalo are struggling to overpower their invasive competitors, and thanks to largely unregulated fishing, the species is in decline. The researchers note that this lack of regulation must be addressed swiftly to preserve this environmentally and economically important species.
“We need to start recognizing bigmouth buffalo for the native, ecological asset that they are,” said lead author Alec R. Lackmann in a statement. “Our neglect of under-appreciated, native species needs to be addressed immediately. Our research has shown that the bigmouth buffalo is one of the longest-lived vertebrates. That alone is something worth preserving and understanding. Among freshwater fish, the bigmouth buffalo is quite exceptional, and they deserve some protection like many other native species in North America have already achieved. The bigmouth buffalo could be treasured one day.”