Original Article: https://blog.theanimalrescuesite.greatergood.com/oldest-tropical-reef-fish/
We hear more and more about the oceans in recent years, mainly due to the impact of global climate change. Coral reefs have not escaped the difficulties, and coral bleaching has caused significant problems for reef fish around the world.
Studies have tried to track this phenomenon, and a recent one published in the journal, Coral Reefs, turned its attention to Western Australia and three species of tropical snapper. They were trying to determine how old the fish were and found that one fish was 81 years old! In other words, the midnight snapper (Macolor macularis) is now the world’s oldest known fish, beating the previous estimate for life expectancy in tropical fish by two decades.
Great snappers were researched from a number of locations, spanning from the central Indian Ocean to the Western Australian coast. They looked closely at the annual growth of their bones to have an estimate of how old the fish were. Think of it as similar to looking at tree rings to determine the age of a tree. According to those samplings, two out of three species turned out to the longest-lived tropical reef fish on record. 11 of the fish were over 60 years old, a red bass (Lutjanus bohar) was 79 years old and the midnight snapper was 81! They discovered the old fish 186 miles west of Broome, Western Australia.
An 80 year old WA snapper is the world’s oldest tropical reef fish, says @aims_gov_au t.co/XcSICfxpkX pic.twitter.com/zy2OmMXuxA
— Au Science Media Ctr (@AusSMC) December 1, 2020
This data does more than push the limit of the age of those tropical fish, it’s important for conservation. Since those fish have lived for decades, it shows that the natural mortality of the species is relatively low. It also means that they have a lower reproduction rate, and that puts their population at risk from overharvesting.
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According to Fish Biologist Dr. Brett Taylor from the Australian Institute of Marine Science (AIMS): “Until now, the oldest fish that we’ve found in shallow, tropical waters have been around 60 years old. We’ve identified two different species here that are becoming octogenarians, and probably older.”
The scientists are now trying to determine how those species are handling differences in water temperatures to see how they will cope when the water gets even warmer. For example, a Red Bass had a life expectancy of around 50 years near the equator, but 80 years at higher altitudes, presumably due to cooler waters.
One thing that is known for certain, it was a complete surprise to realize that some fish have been around since before World War II!
“It survived the Great Depression and World War II,” said Taylor. “It saw the Beatles take over the world, and it was collected in a fisheries survey after Nirvana came and went. It’s just incredible for a fish to live on a coral reef for 80 years.”
Source: The Animal Rescue Site Blog
