Researchers have discovered several individuals of three species of buffalo fish that have survived since 1918, likely due to their isolated environment and evolutionary adaptations.
These fish can be found in oases, streams, or other bodies of water in the desert, often living in isolated conditions that allow them to adapt to harsh environments. The study, published in the journal Scientific Reports, focuses on the species inhabiting Apache Lake in the southwestern Arizona desert, including the bigmouth buffalo, smallmouth buffalo, and black buffalo. These fish are members of the genus Ictiobus, according to Alec Lackmann, a fisheries biologist and co-author of the study, as reported by Interesting Engineering on November 5.
A buffalo fish that has lived for a century in Apache Lake. (Photo: University of Minnesota Duluth)
To determine the age of the buffalo fish, the research team extracted otoliths from the fish’s skull. Otoliths are tiny stone-like structures that grow continuously throughout a fish’s life, adding a new layer each year. Scientists can determine the age of fish by analyzing otoliths under a compound microscope and counting the layers like tree rings. This discovery revealed that some buffalo fish introduced to Arizona in 1918 are likely still alive today.
To confirm the results, the research team also employed radiocarbon dating methods. Among the analyzed individuals, five exceeded 100 years of age, astonishing scientists with the longevity of this species. Furthermore, older buffalo fish exhibit lower stress levels and more effective immune systems, as evidenced by blood analyses showing lower neutrophil and lymphocyte counts.
In 2019, a 10 kg individual was caught in Pelican Rapids, Minnesota, USA, with an age of 112 years recorded. By January 2023, the team discovered a 127-year-old specimen in Saskatchewan, Canada. This makes the bigmouth buffalo one of the longest-living freshwater fish species in the world. According to the research team, bigmouth buffalo have adapted to survive long reproductive cycles, enduring up to 50 years without spawning under unfavorable conditions.
“Initially cultivated in fish farms and ponds along the Mississippi River in the Midwest, the government stocked buffalo fish in Roosevelt Lake (upstream from Apache Lake) in 1918,” the research team stated.
This species has developed the ability to live long to compensate for extended non-spawning periods.
Roosevelt Lake has become a commercial fishing area over time, but the fish population in Apache Lake has remained largely unaffected. Recently, fishermen have discovered effective ways to catch buffalo fish in Apache Lake using poles and lines. Some catch-and-release fishermen have started to notice unusual black and orange spots on the fish they caught, prompting research efforts into this pattern. They contacted Lackmann to conduct scientific analyses on some of the fish, ultimately uncovering the longevity of freshwater species in this desert lake.
Bigmouth buffalo not only exhibit astonishing longevity but also endure high turbidity and low oxygen levels. This resilience enables them to maintain robust vitality in conditions with dissolved solids levels as high as 200 ppm.
However, one of the challenges facing this species is human activities such as dam construction, which disrupt their reproductive cycles.
Although buffalo fish are not on the conservation list in the USA, scientists in Canada are focusing research on this species to raise community awareness. Bigmouth buffalo are often mistaken for common carp, an invasive species considered harmful, and are seen as “trash fish” due to their unpopularity as food. However, their enduring existence plays a crucial role in the local ecosystem and is noteworthy for scientists studying the longevity of vertebrates.
