Approximately 97 percent of fish species have otoliths. They’re tiny stone-like structures that grow throughout the fish’s lifetime, forming a new layer each year. When processed properly, scientists like Lackmann can examine the otolith with a compound microscope and count the layers, like the rings on a tree, and learn the age of the fish.Unparalleled longevity for freshwater fishes.
A fishery of catch-and-release buffalofish angling that has not only increased our knowledge of fisheries, but also our understanding of how buffalofishes can be identified and recaptured across years, including uniquely-marked centenarians. Buffalofishes are native to central North America, including Minnesota, but those in this recent study were found in Apache Lake, a reservoir in the desert southwest. Originally reared in hatcheries and rearing ponds along the Mississippi River in the Midwest, the government stocked buffalofishes into Roosevelt Lake , Arizona in 1918.
By studying the fishes collected at the angling event and analyzing their otoliths for age, Lackmann found that some of the buffalofishes from the 1918 Arizona stocking are likely still alive today, and that most of the buffalofishes in Apache Lake hatched during the early 1920s. More importantly, they discovered that the three different buffalofish species found in the lake had ages more than 100 years.