Maximum age and missing time in the vertebrae of sand tiger shark
Accepted on 08. October 2013
Maximum age and missing time in the vertebrae of sand tiger shark (Carcharias taurus): validated lifespan from bomb radiocarbon dating in the western North Atlantic and southwestern Indian Oceans
Michelle Passerotti, Allen Andrews, John Carlson, Sabine Wintner, Kenneth Goldman, Lisa Natanson
ABSTRACT :
Bomb radiocarbon analysis of vertebral growth bands was used to validate lifespan for sand tiger sharks, Carcharias taurus, from the western North Atlantic (WNA) and southwestern Indian Oceans (SIO). Visual counts of vertebral growth bands were used to assign age and estimate year of formation (YOF) for sampled growth bands in eight sharks from the WNA and two sharks from the SIO. Carbon-14 results were plotted relative to YOF for comparison with regional Î14C reference chronologies to assess accuracy of age estimates. Results from the WNA validated vertebral age estimates up to 12 years, but indicated ages of large adult sharks were underestimated by 11-12 years. Age was also underestimated in adult sharks from the SIO by 14-18 years. Validated lifespan for C. taurus individuals in this study reached at least 40 years for females and 34 years for males. Findings indicate the current age-reading methodology is not suitable for estimating the age of C. taurus beyond approximately 12 years. Future work should investigate whether vertebrae of C. taurus record age throughout ontogeny, or cease to be a reliable indicator at some point in time.
Marine & Freshwater Research, MF13214