A mysterious coelacanth fish can live 100 years – study | marine life

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The coelacanth – a giant, mysterious fish that has survived since the days of the dinosaurs – can live up to 100 years, according to a study.

The slow-moving fish, which grow to the size of a human, are dubbed a “living fossil” and also grow at a very slow rate.

Females do not reach sexual maturity until their late 50s, according to the study by French scientists, while male coelacanths are sexually mature between 40 and 69 years old. And perhaps strangest of all, researchers believe that pregnancy in fish lasts about five years.

Coelacanths, which have been around for 400 million years, were thought to be extinct until they were found alive in 1938 off the coast of South Africa. Scientists have long believed that coelacanths live for around 20 years.

But by applying a standard technique for dating commercial fish, French scientists have calculated that they actually live for almost a century, according to a study in the journal Current Biology published Thursday.

Coelacanths are so endangered that scientists can only study specimens that have already been caught and died.

In the past, scientists calculated the age of fish by counting large lines on a specific coelacanth scale. But French scientists found they were missing smaller lines that could only be seen using polarized light – the technique used to determine the age of commercial fish.

Bruno Ernande, a marine evolutionary ecologist at the French Marine Research Institute and co-author of the study, said polarized light revealed five smaller lines for every large one. The researchers concluded that the smaller lineages correlated best with a year of coelacanth age – and this indicated that their oldest specimen was 84 years old.

Using this technique, scientists studied two embryos and calculated that they were both five years old. So, Ernande said, they calculated that pregnancy lasts at least five years in coelacanths.

That five-year gestation is “very strange” for fish or any other animal, said Harold Walker of the Scripps Institution of Oceanography in San Diego, Calif. He was not part of the research.

Even though coelacanths aren’t genetically related to other deep-sea creatures such as sharks and rays, they age slowly, Ernande said. Sharks can live for hundreds of years.

“They might have developed similar life histories because they share similar type habitats,” he said.

This article was last modified on June 18, 2021. The two embryos studied in the research were both found to be five years old, not five and nine as an earlier version claimed.

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