The great mystery about a unique species of fish was solved by researchers at the Australian National University (ANU).
Scientists have known that Lungfish shares some traits with people – such as the ability to breathe air through the lungs – but a new study proves that they also have a similar life span, potentially up to 80 years.
Dr. Stewart Fallon of the Earth Science Research School says Lungfish has been on the list of endangered species in Australia for decades, but this new research could change it.
"One of the main questions is that no one knew their longevity," said Dr. Fallon.
"A lot of fish have what is called Otolith-basically is a solid stone in their inner ear. As the fish grows, the stone also grows and usually has few annual markers so we can count and know how old the fish is – but there is no lungfish that stone.
The second major question is to get an ears stone that you usually have to kill the fish – so you obviously would not want to do the dangerous thing. "
Dr. Fallon and his team, in collaboration with the University of Griffith, Seqwater, the Queensland Department of Natural Resources, Mines and Energy and the Queensland Agricultural and Fisheries Department, have come up with a new approach.
Their technique involves measuring the amount of carbon 14 in Lungfish scales to determine the age of the fish.
The group found it could put fish on the "bomb curve" used to determine the amount of carbon 14 in the atmosphere.
The curve has a distinct shape, beginning to grow in the mid-'50s with the appearance of a nuclear weapon and peak in 1963, when the Treaty on the Prohibition of Nuclear Probe came into force.
"Since then, carbon is basically mixed with all the carbon on Earth," said Dr. Fallon.
"So we have this special curve, and when we tested the fish, we managed to reproduce this curve and say when the fish was born."
The ANU team spent around 1200 radio-carbon measurements over several years and found fish at the age of about three to 78 years.
This is an important breakthrough since researchers have been struggling to find any evidence of a young fish, which has led to concerns that aging is aging and that fish will eventually disappear.
"People have been researching these fishes for 80 years or more. There are anecdotes that some fish in the River Brisbane move from one of the other rivers at the beginning of the twentieth century, because they were already concerned about the population." Fallon said.
Dr. Fallon and his colleagues also noticed that there had been fish for a long time.
"For example, in the Mary River in the seventies and eighties, we have not seen many born fish."
"I do not really know how they have survived in Australia for so long, they like to put their eggs in shallow parts of the river where there are egg plants to which they can hold.Whenever we have big floods, only the erasures are cleared, so at these times we can find that there were large floods just before that, and then it takes several years for the plants to grow again.
"If you're trying to figure out a particular population, this kind of information is pretty critical and gives us a whole beautiful background of information that did not exist before."
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