Most of the time when sharks are in the headlines it’s because The SyFy Channel has released another low budget movie where they are flying out of tornado or because a person who willingly ventured into the shark’s habitat got bitten by one. That means public relations for the cartilaginous fish who have swum in the world’s oceans for at least the past 420 million years and range from the length of a cigar (the dwarf lanternshark) to over 40 feet (the Whale Shark) aren’t exactly great. However news this week shows just how cool these big fish can be as scientists investigating the Greenland Shark finally figured out how to somewhat accurately gauge the age of one of the most mysterious species of shark. As said earlier, sharks are cartilaginous, meaning they don’t have many if any solid bones so very few clues to the age of these fish exist. Some sharks get calcium growths on their backbones which scientists can look at like the rings of a tree.
Greenland Shark does not get these growths but hard tissue does metabolize on their eye lens (the sharks are nearly blind even in good health) so scientists found a way to isolate the growths from when the sharks were pups and then use radiocarbon dating (a practice usually reserved for animals suspected of living a very long time) on 28 specimens, mostly deceased ones caught in fishing nets, and the results are staggering.
The oldest specimen analyzed was a female roughly sixteen feet in length who was at youngest around 270 and at oldest around 500 years old, usually with radiocarbon dating like this scientists like to stick towards the median value which in this case is the four-century mark, making it easily the oldest vertebrate recorded thus far. With this amazing discovery though there should be caution because it was also determined that these slow moving fish reach sexual maturity well after their hundredth birthday which makes them very vulnerable to fishing pressures as their population can only recover so quickly and should fishing uptick to it’s mid-twentieth century highs when sharks were hunted for liver oil these old creatures could find themselves extinct very quickly.
However, if they do manage to survive and if humanity survives with them maybe in the year 2400 they will find a shark that is very young today reaching that four-century threshold as we did this week.
