A new study finds that coelacanths – giant exotic fish that have existed since the time of the dinosaurs – can live as long as 100 years. Dubbed the “living fossil”, this deep, slow-moving fish the size of a man goes against the motto of live fast, die young. This nocturnal fish grows at a very slow pace.
The study said that women do not reach sexual maturity until their late fifties, while men are sexually mature between the ages of 40 and 69. Perhaps the strangest thing is that researchers believe that pregnancy in fish lasts about five years.
The coelacanth, which has been around for 400 million years, was thought to be extinct until it was discovered alive in 1938 off the coast of South Africa. Scientists have long believed that coelacanths live about 20 years. But applying standard techniques for dating commercial fish, French scientists estimate that they actually lived for almost a century, according to a study in Current Biology Thursday.
The coelacanth is so endangered that scientists can only study specimens that have been caught and died. In the past, scientists calculated the age of fish by counting the outlines on the scale of certain coelacanths. But French scientists found that they were missing a smaller line that can only be seen using polarized light – a technique used to date commercial fish.
Polarized light reveals five smaller lines for each outline, said study co-author Bruno Ernandi, a marine evolutionary ecologist at the French Marine Research Institute. The researchers concluded that the smaller stripes correlated better with one year of coelacanth age – suggesting that the oldest sample was 84 years old.
Using this technique, the scientists studied two embryos and calculated that the oldest was five years old and the youngest nine. So, Ernandi said, they believe pregnancy lasts for at least five years in the coelacanth, which is born alive. A five-year gestation period is “very strange” for any fish or animal, said Harold Walker of the Scripps Institution of Oceanography, who was not part of the study.
Ernandi says that although coelacanths are genetically unrelated and show broad evolutionary differences, they age slowly like other populations of sharks and rays. “They may have developed a similar life history because they shared the same type of habitat,” he said.
(This story has not been edited by Devdiscourse staff and is created automatically from a shared feed.)
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