Cape town – The coelacanth, a wondrous fish that was thought to have become extinct with the dinosaurs 66 million years ago before it was unexpectedly found alive and well in 1938 off the east coast of South Africa, still surprises scientists with more surprises.
Scientists said that a new study of these fish, which live in the great depths of the sea and are active at night and are closely related to their incubating environment, live five times longer than previously thought – that is, they live for nearly a century – and that females carry their young for five years, which is the longest known pregnancy period.
Harold Walker of the Scripps Institution of Oceanography, who was not part of the research, said the five-year gestation period is “quite strange” for fish or any animal.
After focusing on two living species of coelacanth, scientists concluded that they develop and grow at a slower rate than any other fish, and females of them do not reach sexual maturity until about 55 years of age, while males sexually mature between 40 and 69 years, a feature that exposes these fish to danger.
Coelacanths are so endangered that scientists can only study specimens that have already been caught and dead.
The researchers used annual growth rings on fish scales to determine the age of the coelacanth, said marine biologist Kélég Mahé of the French Oceanographic Institution, lead author of the study published this week in the journal Current Biology.
Coelacanths, a type of “prehistoric” fish, first appeared in the Devonian period about 400 million years ago, about 170 million years before the emergence of dinosaurs.
When the coelacanth was found alive, it was called a “living fossil”, a description that scientists are now avoiding.