Bigmouth Buffalo: A Freshwater Fish That Never Ages?

Bigmouth Buffalo: The Remarkable Fish That Lives for Over a Century

A Fish That Defies Aging

Recent research has revealed that the bigmouth buffalo, a freshwater fish species, possesses extraordinary longevity, thriving for well over a century while maintaining robust health. However, scientists are increasingly concerned about their declining population.

Every May, large groups of these fish can be spotted in the shallow waters of Minnesota's Rice Lake, navigating through aquatic vegetation. Weighing up to 50 pounds (23 kg), these unique fish are among the longest-living freshwater species globally, with some individuals reaching an astonishing age of over 100 years.

Despite their long lifespan, bigmouth buffalo are not widely targeted for commercial fishing, making them economically insignificant. They are native to North America, spanning from southern Canada—specifically Saskatchewan and Manitoba—down to Louisiana and Texas in the United States.

A Species Resistant to Aging

Scientific studies over the past five years have unearthed remarkable findings about the aging process of these fish. Some individuals have been found to live up to 127 years, with no evident signs of aging-related decline. Instead, their health appears to improve over time.

"These are some of the oldest fish on the planet, yet there is little to no conservation management for this species," states Alec Lackmann, a fish researcher at the University of Minnesota, Duluth.

Lackmann spearheaded a groundbreaking 2019 study that upended previous estimates of the species' lifespan. Prior to this research, experts believed the fish lived only up to 26 years.

Using otoliths—small calcified structures found in fish ears—scientists determined the true age of bigmouth buffalo. By carefully slicing and analyzing these structures, researchers could accurately count growth rings, much like the rings of a tree, to establish age.

A subsequent study published in 2021 further examined the species' health and confirmed an unusual biological phenomenon: these fish do not experience the typical deterioration associated with aging. Instead, they appear to develop stronger immune systems and enhanced bodily functions as they grow older.

"There's still much we don't understand about how these fish maintain such remarkable health into old age," says Britt Heidinger, a biologist at North Dakota State University.

The Mystery of the Missing Young Fish

While the discovery of their impressive lifespan is fascinating, a puzzling question remains: Where are the young bigmouth buffalo?

Lackmann and his team analyzed a sample of 390 fish from Rice Lake and found that 99.7% of them—389 in total—were over 50 years old, with an average age of 79. This means that most of the current population was born before the end of World War II.

Despite successful annual spawning events, young bigmouth buffalo have been mysteriously absent in significant numbers for more than six decades. Scientists suspect that predation from other species may be preventing juvenile fish from reaching maturity, but the exact cause remains unknown.

The absence of younger generations raises concerns about the species' future. Without new fish entering the population, these centenarian survivors could eventually face extinction.

A Call for Conservation

Given the precarious situation, researchers stress the urgency of conservation efforts. Lackmann and his colleagues advocate for protective measures, including fishing regulations in states such as Minnesota, to help sustain the species while scientists work to uncover the root causes of their reproductive challenges.

One prevailing theory suggests that habitat disturbances—such as dam construction—may be affecting the species' ability to thrive. However, further research is necessary to confirm the underlying factors at play.

With increased awareness and proactive conservation policies, experts hope to ensure the survival of this extraordinary fish species, which continues to defy biological aging.