Oldest swimmer in town, shark that lives 400 years
IT is a denizen of the deep that can grow up to 21ft in length and weigh more than 2,000lb.
Now scientists have revealed that the Greenland shark is also the longest-living vertebrate in the world – reaching up to around 400 years of age.
Writing in the journal Science, researchers said the slow-moving giants, found in Scottish waters, surpassed other species known for long life, such as turtles and tortoises. The bowhead whale’s lifespan is around 200 years.
Study leader Julius Nielsen, of the University of Copenhagen and Greenland Institute of Natural Resources, said: ‘Greenland sharks are among the largest carnivorous sharks on the planet and their role as an apex predator in the Arctic ecosystem is totally overlooked.
‘By the thousands, they accidentally end up as by-catch across the North Atlantic, and I hope that our studies can help to bring a greater focus on the Greenland shark in the future.’
Vertebrates are animals which have a backbone or spinal column, including mammals, birds, reptiles, amphibians, and fishes.
According to the Shark Trust, the Greenland shark is ‘a massive species with a heavy cylindrical body and short rounded snout’ that can sometimes be found off Scotland, in the North Sea and part of the English Channel.
Its wider range, according to the trust’s website, includes ‘the east Atlantic from the Seine River mouth, France, to Spitsbergen Island, Russia’ and corresponding latitudes in the western Atlantic.
It can be found in a wide range of waters ranging from coastal shallows to depths of more than 4,000ft and its diet consists of fish and crustaceans, as well as mammals including seals.
The age of sharks can usually be measured by a method akin to using tree rings to age a tree, looking at hard cartilage growth.
But as Greenland sharks’ cartilage is very soft the team, which included scientists from Oxford University, the University of Tromso in Norway and Aarhus University in the Netherlands, used a radio carbon dating method to look at the eye lenses of 28 females accidentally caught during studies of fish stocks off Greenland.
They found the sharks’ average life expectancy was 272 and the females may not reach sexual maturity until aged around 156.
Their paper says the only creature to live longer than the Greenland shark is the ocean quahog – an edible clam that can reach more than 500 years old.