scientists have estimated that some copies of this shark may have 400 years Greenland. / Julius Nielsen
So far the bowhead whale was considered the vertebrate world’s oldest, with an age of about 211 years, but now another marine animal has shattered that mark: Greenland shark . By radiocarbon techniques applied to the lens of the eye, scientists have estimated that some copies of this shark may have 400 years.
For decades, the age of the Greenland sharks ( Somniosus microcephalus ) it has been a mystery. Really very little is known about the biology of this species, which lives in the cold waters of the Arctic and the North Atlantic and can reach five meters long , making him one of the largest in the world.
However, it is known to very slow growth rate: approximately one centimeter per year, which already suggests that these fish enjoy exceptional longevity
. traditional methods used to determine the age of an animal are based on analysis of calcified tissue, but this element is scarce in Greenland sharks.
for this reason, an international team of researchers led by marine biologist Julius Nielsen, University of Copenhagen (Denmark) , has applied techniques radiocarbon dating to the lens of the eyes of 28 females captured randomly.
“We have used only females to minimize the uncertainties associated with specific growth patterns of sex, besides that in the area where the samples environment -the Greenland females are more common and thus have more data were collected, “says Nielsen to Sinc.
the results of the analysis show that the average life expectancy of Somniosus microcephalus is at least 272 years. But also, it was estimated that the two largest collected sharks, 493 cm and 502 cm long, had about 335 and 392 years old , respectively.
According the study, which appears on the cover this week in the journal Science , the Greenland shark can live about 400 years and becomes the longest vertebrate on Earth.
So far borealis or Greenland whales ( bowhead whale ) boasted that honor, with an estimated 211 years life, but with the new data relegate this marine mammal to second place.
the margin of error for the oldest shark we found is 392 ± 120 years, but even if it was the lowest value (392-120 = 272 years), the Greenland shark yet would the animal vertebrate world’s oldest “says Nielsen.
researchers have also calculated that females reach sexual maturity at least when they have 156 years, taking into account previous studies which states that this condition is acquired to exceed 4 meters in length
Regarding the reason why these fish enjoy such a long life, scientists do not have it yet clear. “they are cold-blooded animals that inhabit the icy Arctic waters, so their body temperature is also very low -apunta Nielsen. Probably this low body temperature is related to its low metabolism, but I think there’s something else. Other Arctic fish do not live as long, at all. Hopefully we can discover what makes the Greenland shark alive much. “
The marine biologist remember that very little is known about this species: ” We need more data on its biology and the size of the population to assess their conservation status (if it is threatened and to what extent), in addition to solving many questions about his behavior: how to catch their prey if apparently they are so slow, where they mate and give birth to their young … you really are blind due to a parasite that have eyes? I’m not so sure, despite what can be read online. ” The Greenland shark can still give many surprises.
Original article here
No comments:
Post a Comment