December 18, 2023 — The following was released by NOAA Fisheries:
It’s the “age-old” story—count the rings in shark vertebrae to estimate the age of a shark, like counting the annual growth rings on a tree stump. Or so shark researchers thought, until 2018. That’s when NOAA shark researcher Lisa Natanson and her colleagues reported that the rings on shark vertebrae are not always deposited annually. Instead, they are driven by changes in length and girth over a shark’s lifetime, the rate of which can change over the years. This meant that the ageing keys for many shark species needed to be revised by developing and validating new methods to determine shark ages.
Enter Michelle Passerotti, a shark biologist in the Apex Predators Program at the Northeast Fisheries Science Center’s Narragansett Laboratory. She is developing techniques to revamp shark ageing and correct age estimates where needed in a new era of ageing.
The first crucial step is making sure new methods will accurately predict shark ages by validating traditionally aged samples.