Very limited research has shown that the Greenland shark grows by about 0.5 to 1 cm per year. A shark that was captured and tagged off Greenland in 1936 was recaptured in 1952. In 16 years, the shark’s length had only increased by 6 centimetres. Assuming its growth rate is constant (no growth spurts), one can thus hypothesize that a mature seven-metre specimen could be over 200 years old, making the Greenland shark the longest-living vertebrate on the planet.
— Read on www.dutchsharksociety.org/the-greenland-shark-worlds-oldest/