Arizona Desert Fishes: Oldest Animals Living in Most Unexpected Place

According to a recent study, Arizona desert fishes, which are among the oldest species on Earth, are residing in an unexpected location.

The discovery of the second animal genus in which three or more species with lifespans known to exceed 100 years may pave the way for aging research in a variety of academic fields, including gerontology and senescence, or aging, in vertebrates.

Arizona Desert Fishes: Buffalofishes

The study focuses on three buffalofish species in Minnesota: bigmouth buffalo, smallmouth buffalo, and black buffalo. Misidentification and inadequate fishing regulations threaten these species, often mistaken for invasive carp.

University of Minnesota Duluth (UMD), led by Dr. Alec Lackmann, collaborated with North Dakota State University and conservation anglers from Apache Lake Reservoir in Arizona.

This research seeks to unravel the longevity and aging secrets of these native fish, shedding light on their ecological importance. It underscores the need for improved protection and recognition of these species, as they hold the potential to offer valuable insights into aquatic ecosystems.

Aging, Longevity, and Fish Otoliths

Lackmann highlights the potential wealth of aging and longevity data within the Ictiobus genus. This study unveils this untapped resource, offering insights into vertebrate aging, potentially even for humans. It prompts the question: What's the secret to buffalofishes' seemingly negligible senescence?

Lackmann's prior research in 2019 pushed the boundaries of our understanding. He expanded the bigmouth buffalo's maximum age from 25 to over 100 years, using a more refined aging method. Instead of analyzing scales, he extracted otoliths (earstones) from inside the fish's cranium and then thin-sectioned them to determine age.

Around 97% of fish species possess otoliths, which accumulate annual layers, much like tree rings. With careful processing, scientists like Lackmann can examine these structures under a microscope, counting the layers to unveil a fish's age. This method opens doors to a deeper understanding of the aging process in various species, including buffalofishes.

Oldest Animals Living in Most Unexpected Place

Buffalofishes, native to central North America, were the focus of this study, sourced from Apache Lake in the desert southwest. Originally stocked in Roosevelt Lake, Arizona, in 1918, they were raised in Midwest hatcheries. While Roosevelt Lake was commercially fished, Apache Lake's fish population remained largely untouched until recent catch-and-release conservation anglers discovered them.

Noticing unique orange and black spots on the fish, they reached out to Lackmann, who had conducted previous research on buffalofishes. Stuart Black, an Arizona angler, invited Lackmann on a fishing expedition to collect specimens for scientific study.

Lackmann's examination of fish from the angling event revealed remarkable findings. Some of the buffalofishes stocked in Arizona in 1918 may still be alive today, and the majority of Apache Lake's buffalofishes hatched in the early 1920s. Notably, all three buffalofish species in the lake had ages exceeding 100 years, a phenomenon unprecedented in freshwater fish worldwide.

This discovery holds immense promise for future research. Lackmann envisions the opportunity to monitor these long-lived species to delve into their DNA, physiology, disease resistance, and aging processes, offering invaluable insights into gerontology. The Ictiobus genus possesses the potential to significantly contribute to this field. Apache Lake could evolve into a hub for diverse scientific investigations, paving the way for groundbreaking discoveries in the years to come.