Study finds Coelacanth, a human-sized Dinosaur era fish can live for 100 years
The coelacanth – a giant, mysterious fish from the time of the dinosaurs can live for 100 years, according to the findings of a recent study.
Nicknamed “living fossil”, the coelacanth is a slow-moving fish which can grow to be the size of a human although the rate of growth is at a very slow pace.
The study by French scientists has made some strange discoveries. While earlier the scientists believed that the fish can only survive for up to 20 years, it was discovered that the average lifespan of this fish is 100 years.
They also discovered that pregnancy in this fish lasts for approximately five years and that while the females of the species don’t reach sexual maturity until their late 50s, male coelacanths achieve sexual maturity at the age of 40 to 69 years old.
The average lifespan was deduced by applying a standard technique for dating commercial fish. The findings of the French scientists’ study have been published in the journal Current Biology.
The species is so endangered that scientists can only study specimens already caught and dead.
The technique used to calculate the fish age involves lines that are present on a very specific scale on the coelacanth’s body. Earlier scientists were calculating fish ages by counting the big lines on this scale. But the French scientists involved in this study discovered that they’ve been missing smaller lines, which were only visible under polarised light.
Bruno Ernande, co-author of the study, said that inspection under polarised light revealed that there were five smaller lines for every big one. Using this information, the researchers concluded that the smaller lines correspond better with a year of coelacanth age, which then led them to ascertain that the age of their oldest specimen was 84 years old.
The scientists also used this technique to study two embryos. They calculated that the largest one was five years old and the youngest nine years old. Based on this, they calculated that pregnancy lasts at least five years in coelacanths.
According to Harold Walker of Scripps Institution of Oceanography in San Diego, California, a five-year gestation is “very strange” for fish or any animal. He was not part of the research.
According to Ernande, even though coelacanths are not genetically related to deep-sea creatures such as sharks and rays, the species’ share similar slow aging. Similar to the ‘living fossil’, sharks can also live to be hundreds of years old.
He added that, “They might have evolved similar life histories because they are sharing similar type habitats,”.