How lengthy do Greenland sharks dwell?

 Close-up image of a greenland shark taken at the floe edge of the Admiralty Inlet, Nunavut.

Shut-up picture of a greenland shark taken on the floe fringe of the Admiralty Inlet, Nunavut.

Picture credit score – Hemming1952 | Wikimedia Commons | Used below the Inventive Commons Attribution-Share Alike 4.0 Worldwide | Modifications: measurement

Scientists have suspected for some time that Greenland sharks lived extraordinarily lengthy lives, however they didn’t have a technique to decide how lengthy. The age of different shark species may be estimated by counting progress bands on fin spines or on the shark’s vertebrae, very similar to rings on a tree. Greenland sharks, nonetheless, haven’t any fin spines and no exhausting tissues of their our bodies. Their vertebrae are too smooth to kind the expansion bands seen in different sharks. Scientists may solely guess that the sharks lived a very long time based mostly on what they knew — the sharks develop at a really sluggish charge (lower than 1 cm per 12 months) they usually can attain over 6 meters in measurement.

However current breakthroughs allowed scientists to make use of carbon relationship to estimate the age of Greenland sharks. Contained in the shark’s eyes, there are proteins which are fashioned earlier than beginning 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 had been bycatch in fishermen’s nets. The biggest shark they discovered, a 5-meter feminine, was between 272 and 512 years outdated in response to their estimates. Carbon relationship can solely present estimates, not a definitive age. Scientists proceed to refine this technique and will 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 clarify this lengthy lifespan is that the Greenland shark has a really sluggish 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 recognized 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 sluggish metabolism may clarify the shark’s sluggish progress, sluggish getting old, and sluggish motion — its prime pace is below 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 outdated. 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, the vast majority of Greenland sharks that find yourself in fishing nets and contours now are caught by chance. Lowering bycatch is essential in conserving this distinctive species.