Scientists have suspected for some time that Greenland sharks lived extraordinarily lengthy lives, however they didn’t have a approach to decide how lengthy. The age of different shark species could be estimated by counting progress bands on fin spines or on the shark’s vertebrae, very similar to rings on a tree. Greenland sharks, nevertheless, haven’t any fin spines and no exhausting tissues of their our bodies. Their vertebrae are too gentle to kind the expansion bands seen in different sharks. Scientists might solely guess that the sharks lived a very long time primarily based on what they knew — the sharks develop at a really gradual charge (lower than 1 cm per 12 months) and so they can attain over 6 meters in dimension.
However latest breakthroughs allowed scientists to make use of carbon courting to estimate the age of Greenland sharks. Contained in the shark’s eyes, there are proteins which might be shaped earlier than delivery and don’t degrade with age, like a fossil preserved in amber. Scientists found that they might decide the age of the sharks by carbon-dating these proteins. One research examined Greenland sharks that have been bycatch in fishermen’s nets. The most important shark they discovered, a 5-meter feminine, was between 272 and 512 years previous in line with their estimates. Carbon courting can solely present estimates, not a definitive age. Scientists proceed to refine this technique and should present extra correct measurements sooner or later. However even on the decrease finish of the estimates, a 272-year lifespan makes the Greenland shark the longest-lived vertebrate.
One idea to elucidate this lengthy lifespan is that the Greenland shark has a really gradual metabolism, an adaptation to the deep, chilly waters it inhabits. A NOAA remotely operated car doing a dive off New England encountered a Greenland shark at a depth of 783 meters, however these sharks are identified to dive as deep as 2,200 meters. They’re additionally the one shark that may face up to the chilly waters of the Arctic Ocean year-round.
The gradual metabolism might clarify the shark’s gradual progress, gradual growing old, and sluggish motion — its prime velocity is underneath 2.9 kilometers per hour. As a result of the sharks develop so slowly, they aren’t thought to succeed in sexual maturity till they’re over a century previous. Meaning eradicating mature Greenland sharks from the ocean impacts the species and the ecosystem for a lot of a long time. Although the Greenland shark was once hunted for its liver oil, nearly all of Greenland sharks that find yourself in fishing nets and features now are caught accidentally. Reducing bycatch is crucial in conserving this distinctive species.