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Figure: Carbon dating confirms that Ictiobus cyprinellus is the longest known freshwater fish.
For any animal, birth, old age, illness and death are inevitable processes of life cycle. However, many animals have strong vitality, which frees them from the limitations of natural rules to some extent, and their life span is longer than that of the same species or most species.
Recent studies using radiocarbon dating have shown that an Ictiobus cyprinellus can live up to 112 years, nearly four times longer than the previously known maximum age (26 years). Originated in North America, the giant-mouthed cochineal can grow to nearly 40 kilograms. It is the oldest freshwater bony fish with about 12,000 varieties.
Solomon David, an assistant professor at Nichols State University in Louisiana, said: A fish that has lived for more than 100 years? Its absolutely a great thing!
In recent years, thanks to more advanced testing techniques, scientists have found that many fish, such as Greenland sharks, can live much longer than previously thought. Although the age of fish is a basic feature of its biology, we usually know little about the life expectancy of fish.
Before researchers measured the age of giant-mouthed carmine, they had a hunch that freshwater fish, mainly in the northern United States and southern Canada, lived longer than people thought.
The team removed thin Otoliths from 386 wild giant-mouthed carmine. Otolith is a small calcified structure that helps fish maintain balance in swimming. They then counted the growth rings on each otolith with a microscope. Their first statistics show that these fish have lived for 80 or even 90 years.
When Alec Lackmann, the lead researcher, first saw the numbers, his response was, No way!
To verify this, Lachman and his colleagues turned to radiocarbon dating. This is an effective method to compare the amount of carbon-14 isotopes in animal tissues with the concentration of carbon-14 released during the mid-20th century atomic bomb test. This method has been used to determine the age of animals ranging from human remains to sharks.
A recent study, published in the Journal of Communication Biology, showed that researchers used radiocarbon dating to cross-check the results of otolith tests in giant-mouthed cow carmine, confirming their estimates of otolith life, i.e. between 80 and 90 years old.
A total of five giant-mouthed cochineals are over 100 years old, but a female caught near Pelican Rapids, Minnesota, has reached the age of 112, becoming the worlds longest-lived freshwater fish record holder.
Aging of fish
In Lachmans test of 16 giant-mouthed coirs over 80 years of age, they found another surprising fact: many fish were born before 1939, suggesting that their reproductive failure lasted for decades. The possible cause of this failure is the construction of the dam, which hinders the ability of fish to return upstream to spawn.
In fact, giant-mouthed carmine is often referred to as garbage fish because they are usually not eaten and are misclassified as invasive species, such as common carp. But Lachman says, We should stay away from the word because it denigrates too many native species.
David, an assistant professor at Nichols State University in Louisiana, agrees. This, he said, automatically reduces the value of the creature itself. As far as the giant-mouthed carmine is concerned, it plays an important role in maintaining the health of local rivers, that is, replacing the invading carp.
Almost all States in the United States where giant-mouthed cochineal is found have no capturing restrictions on giant-mouthed cochineal. The fish is not threatened in the United States, but is specially protected in Canada.
Lachman and David hope to discover that the amazing longevity of giant-mouthed cochineal will help raise its popularity. David said, I hope to learn the cool fact that people can observe the species more closely.
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