Tropical reef fish, 81, is the oldest ever to be discovered by scientists

The 81-year-old fish was discovered in the Rowley Shoals area of Western Australia, which is pictured here.

(CNN)Scientists have discovered what they say is the oldest tropical reef fish recorded anywhere in the world -- an 81-year-old midnight snapper caught off the coast of Western Australia.

The octogenarian fish, which is old enough to have lived through World War II, was found by the Australian Institute of Marine Science at the Rowley Shoals, about 300 kilometers (186 miles) west of Broome, as part of a study into the longevity of tropical fish.
Researchers looked at three species they said were not commonly targeted by commercial or recreational fishing in Western Australia and the Chagos Archipelago in the central Indian Ocean. The species included red bass, midnight snapper and black and white snapper.
The 81-year-old midnight snapper was identified alongside 10 other fish over the age of 60, including a 79-year-old red bass that was also caught in the Rowley Shoals -- an area spanning three coral reefs at the edge of Australia's continental shelf.
Marine scientists determined the age of the fish by dissecting them and studying their ear bones, or otoliths, which contain annual growth bands that can be counted in a similar way as tree rings.
Brett Taylor, a fish biologist who led the study, said the midnight snapper beat the previous record holder by two decades.
"Until now, the oldest fish that we've found in shallow, tropical waters have been around 60 years old," he said.
"We've identified two different species here that are becoming octogenarians, and probably older."
Taylor said the research would help scientists understand how fish length and age will be affected by climate change.
"We're observing fish at different latitudes -- with varying water temperatures -- to better understand how they might react when temperatures warm everywhere," he said.
The octogenarian fish is not the oldest sea-dwelling creature to exist.
Greenland sharks, which are native to Arctic seas, are the longest-living vertebrate on Earth. University of Copenhagen researchers estimated that these sharks live to at least 400 years, nearly two centuries longer than the whales.