That Shark You Ate May Be Centuries Old

Scientific research has brought to light that the Greenland shark, served in Iceland as the traditional dish hákarl, has a lifespan that can stretch across centuries.

Scientists have for a long time suspected that the shark, which is the largest fish in Arctic waters, probably takes a very long time to grow. However, their exact age has been a puzzle, as sharks do not have bones that can be measured to assess their age. Ars Technica reports that by tracking the chronology of the shark’s eye lens, Julius Nielsen and a team of researchers have made a startling discovery about just how old Greenland sharks can get.

By also tracking for the presence of residual radiation from repeated atmospheric nuclear testing in the 1960s, they found that Greenland sharks can live for centuries. In fact, the oldest amongst them was found to be in the neighbourhood of 500 years old, with the animal taking a whole century just to reach sexual maturity for reproduction.

“This investigation reveals that the Greenland shark is among the longest-lived vertebrate species, with a life expectancy exceeded by only one other ocean dweller (a species of whale),” Ars Technica reports. “Since it takes them more than a century to reach reproductive age, conservation efforts are important to help keep this population from dwindling.”

The Greenland shark is an Icelandic delicacy. It is typically putrefied for months before being hung up in the sea air to dry (as shown above), and then eaten raw. For many first arrivals to Iceland, it is a must-try, and usually met with decidedly mixed reviews.

The study in its entirety can be read here.