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Koalakanth may live for a century. This is not great news


African coelacanths are Very Old. The origin of fossil evidence dates back to about 400 million years ago, and scientists believed that it became extinct until 1938, when the curator was Marjorie Courtenay Latimer I noticed a live person in a fishing net.

Found off the southeast coast of Africa, Hollow It also lives a long time – scientists suspect about 50 years. But proving that age was difficult. (Coelacanths are considered endangered and accustomed to deeper waters, so scientists can’t just put their young in a tank and start a temporary run.) . “We were surprised,” says Bruno Ernandi, the marine ecologist who led the study. He says the new estimated age “was nearly a century”.

His team from the French Institute for the Exploitation of the Sea, or IFREMER, found not only that individuals can live to close to 100 people but also have gestation periods of at least five years, and may not sexually mature until at least adulthood. 40. consequences Posted on Thursday in Current Biology. This slow life highlights the importance of conservation efforts for this rare species, which has been classified as “critically endangered” in IUCN Red List. There are only about 1,000 in the wild, and their long pregnancies and late maturation are bad news for the resilience of their populations in the face of humans. “It’s more at risk than we previously thought,” says Ernandi.

“It will have dire consequences,” agrees Daniel Pauli, an ichthyologist from the University of British Columbia, who was not involved in the study. Pauly is the founder of FishBase, a biological and ecological database on tens of thousands of species. If a fish takes decades to reproduce, killing it eliminates its ability to replenish its numbers. “A fish that takes 50 years to reach maturity, versus 10 years, is five times more likely to be in trouble,” he says.

thick coelacanth Scales are up to two inches long, and for decades, ichthyologists have been debating how to read these scales for signs of age. In the 1970s, researchers noticed small calcified structures on them. They believed that rings are signs of age, like tree rings. But they differed in how they were calculated: some believed that each sign denoted one year; Others believe that seasonal fluctuations create two episodes per year. At the time, a best guess would have put life expectancy at around 22 years. This finding, which means a 6-foot, 200-pound coelacanth at a 17-year-old, indicates that they are growing very fast: “They will grow as fast as tuna, which is crazy,” says Pauli.

It’s crazy because these are animals with slow metabolisms, which indicates slow growth. The hemoglobin in coelacanths is adapted to a slow metabolism, which means that they cannot take in enough oxygen to support a fast-growing fish. Some argue that small gills are further evidence of oxygen limitations. They also lead very passive lifestyles, resting most of the day in caves and slowly lumbering across Ocean Twilight Zone, down at 650 feet and below, when you adapt to movement. “Overwhelmingly, the biological features were indicative of a slow-lived fish,” says Ernandi.

In addition, scientists who track the lives of individual coelacanths have recognized that 20 years is very low. in the eighties, researchers She began sending submarines and RVs into a cave that harbored 300 to 400 coelacanths. They have been going back to this place for more than 20 years. During each visit, they recognized individuals by their distinctive white markings. Only about three or four fish in this group will die, and an equal number of new fish will be born each year. This observation provided stark evidence that coelacanths live long lives – even more than 100 years. This study argues.



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