Scientists have found the world’s oldest tropical reef fish off the coast of Western Australia. An 81-year-old yellow snapper has beaten the previous record holder by over 20 years.
A fish that is believed to have lived through World War II was found by the Australian Institute of Marine Science at the Rowley Shoals, about 300 kilometers west of Broome, as part of a study on the longevity of tropical fish.
The scientists examined three species of fish that are not affected by fisheries in the area: the copper snapper (Lutjanus argentimaculatus), the midnight or yellow-eyed snapper (Macolor macularis), and the black and white snapper (Macolor niger). By examining the ear bones, which contain annual growth bands, the researchers were able to determine the age of the fish. Scientists involved in this study state that counting fish growth bands works in a similar way to counting tree rings.
Brett Taylor, a fish biologist who led the study, says the yellow snapper beat the previous record holder by two decades. Because the oldest fish in tropical waters are barely 60 years old.
The study also aims to clarify how the life and age of fish is affected by climate change. Different fish are observed at different water temperatures in order to find out how they react when the water temperature rises everywhere.
Freshwater fish are getting older
But freshwater fish can also get older than expected. Researchers were able to determine the age of a loud mouthed buffalo fish. At a proud 112 years, the animal is four times as old as its normal estimated life expectancy of around 26 years.
From 2011 to 2018, scientists captured, measured, photographed, and tagged loud mouth buffalo fish in the Pelican River and Otter Tail River in Minnesota before releasing them back into the water. 386 fish were dissected to determine their age using the otoliths. The scientists were able to determine an age of up to 90 years.
With the help of radiocarbon dating, the results were checked again. The method is based on the decay of an isotope of carbon. This enables the age of an organism and the time of death to be determined precisely. This enabled researchers not only to determine the age of the fish, they also found much older specimens, such as the 112-year-old loud-mouthed buffalo fish.
But there is also bad news: the fish population is declining. Dams built in the 1930s prevent access to spawning grounds. And overfishing is also a big problem. Since the Americans tend to view loudmouth buffalo fish as superfluous, it is precisely for this reason that they are overfished and their very existence is threatened.
Scientists have no understanding of this: they are calling for urgent conservation measures to enable existing populations to recover. They now hope that this discovery will lead to a greater appreciation of the loud mouthed buffalo fish.
But neither the yellow-eyed snapper nor the loud-mouthed buffalo head are the oldest living animals in bodies of water. Greenland sharks, native to the arctic seas, are the longest vertebrates on earth. Some researchers from the University of Copenhagen estimated that these sharks can live up to 400 years. Almost two centuries longer than whales.
