The coelacanth may live for a century.This is not good news


African coelacanth is Very old.Fossil evidence indicates that their origin can be traced back to about 400 million years ago. Scientists believe that they did not become extinct until 1938 when the museum curator Marjorie Courtney-Latimer A live one was found in the fishing net.

Found on the southeast coast of Africa, Coelacanth Can live a long time-scientists suspect About 50 years. But it has been difficult to prove longevity. (The coelacanths are endangered and are accustomed to deep water, so scientists cannot just put their children in a tank and start timing.) Now a French research team examines their scales with polarized light to determine that they may live longer and longer. Long. “We were taken aback,” said Bruno Ernande, a marine ecologist who led the study. He said the new life expectancy is “nearly a century.”

His team from the French Institute of Marine Development (IFREMER) found that not only can individuals live to nearly 100 years old, but their gestation period is at least five years, and they may not be sexually mature at least until they reach adulthood40. result Posted on Thursday Current biology. This slow-motion life highlights the importance of protecting this rare species, which has been marked as “critically endangered” IUCN Red ListThere are only about 1,000 in the wild, and their long pregnancy and late maturity are bad news for their population’s ability to resist humans. “It is more endangered than we previously thought,” Ernand said.

“This will have huge consequences,” agreed with Daniel Pauly, an ichthyologist at the University of British Columbia who was not involved in the study. Poly is the creator of FishBase, a database of biological and ecological information about tens of thousands of species. If a fish takes decades to spawn, then killing it will eliminate its potential to replenish the population. “A fish that takes 50 years to mature, instead of 10 years, is five times more likely to encounter trouble,” he said.

Coelacanth has a thick Scales up to two inches long, and ichthyologists have been debating how to read these scales for signs of age for decades. In the 1970s, researchers noticed small calcified structures on them. They think that annual rings are age markers, just like tree rings. However, they disagree on how to calculate them: some people think that each mark represents a year; others think that seasonal flipping produces two rings per year. At the time, the best guess was that their life expectancy was about 22 years. This conclusion means that the 6-foot-200-pound coelacanth is 17 years old, which means that they grow very fast: “They grow as fast as tuna, which is crazy,” Pauli said.

This is crazy, because these animals have a slow metabolism, which should indicate slow growth. The hemoglobin of coelacanths adapts to a slow metabolism, which means they cannot absorb enough oxygen to support fast-growing fish. Some people think their small gills are further evidence of oxygen limitation.They also lead a very passive lifestyle. They spend most of the day resting in caves and slowly walking through Twilight zone of the ocean, At 650 feet and below, when they condescended to walk around. “In most cases, the biological characteristics point to a slow-lived fish,” Ernand said.

In addition, scientists who track the lives of individual coelacanths already know that 20 years are too short. In the 1980s, Researchers Begin to send submersibles and remote-controlled vehicles to a cave containing 300 to 400 coelacanths. They have returned to this place for more than 20 years. During each visit, they identified individuals by their characteristic white markings. Each year, only about three or four fish in this group will die, and the same number of new fish will be born. This observation provides surprising evidence that the coelacanth has a long life span—even more than 100 years. The study believes.



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