Great White Sharks were originally thought to only live up to around 25 – 30 years old, but a new study suggests that their lifespan may be far longer than previously thought, and that Great White Sharks may actually live well into their 70’s!
Previous research relied on counting the growth band pairs on a sharks vertebrae to determine it’s age and growth rate, much like counting the rings on a tree, under the assumption that each band was equal to one year. Although, in many cases, this method is effective and true for part of or all of a specie’s life, at some point growth rates and age are not necessarily in sync. Growth rates typically slow as sharks age and deposition rates in vertebrae can change once sharks reach sexual maturity, resulting in band pairs which are so thin that they are unreadable Therefore, the age of a shark is frequently underestimated.
In a recent study, experts from Woods Hole Oceanographic Institution in Massachusetts, United States used radiocarbon dating technology to examine the backbones of four male and four female adult Great White Sharks from the north-western Atlantic Ocean, which were caught between 1967 to 2010. Bomb radiocarbon dating is thought to be one of the best techniques to determine the age of long-lived species such as sharks, and the discrete radiocarbon pulse in the environment caused by the detonation of nuclear bombs in the 1950s and 1960s was used as a “time stamp” for the study. The radiocarbon levels incorporated into the band pairs were measured and related to a reference chronology to determine the age of the sharks.
According to the findings based on this research method, the largest male Great White Shark was found to be 73 years old, and the largest female was 40 years old.
Great White Sharks are considered a vulnerable species worldwide, and by knowing how long they live and how fast they grow, this can help assist with conservation efforts to protect this species. For further information on the study, you can check out the Woods Hole Oceanographic Institution’s website.
This latest study brings joy to all of us at African Shark Eco-Charters, and extreme hope that we may still be able to see our favourite regular Great White Sharks at Seal Island for many years to come! Join African Shark Eco-Charters on one of our breaching and cage diving trips and let us show you why we love our Great White Sharks so much.