Catch me (again) if you can: length–age relationship for white sharks (Carcharodon carcharias) from capture–mark–recapture data

Reliable length–age relationships are essential for the effective management of elasmobranchs. For white sharks ( Carcharodon carcharias ), traditional growth studies, have produced inconsistent results, aggravating the already complex management of this species. Recently, efforts have been made to find non-lethal alternatives that use the length increments from capture–mark–recapture (CMR) data to estimate growth in elasmobranchs. Using over 7 years of CMR data from a novel non-lethal bather protection program in New South Wales (Australia), this study aimed to estimate white sharks’ first growth curve independent from vertebral band pairs, inferring ages-of-maturity and longevity. A Bayesian formulation of the Fabens method for estimating growth from CMR was used, yielding statistically well-supported results. The growth rate (21.7 ± 6.4 cm year −1 ) calculated is the most robust estimate currently available for immature white sharks based on direct measurements. The growth parameters, theoretical maximum length ( L ∞ , 510.6 cm fork length) and growth coefficient ( k , 0.074 -year ), are comparable with previous estimates from traditional vertebral counts. Although based almost exclusively on immature individuals, the sex-specific growth curves suggest that female sharks grow faster and larger than males. Despite wide credible intervals, the estimated ages-of-maturity (female: 18 years, male: 11 years) and theoretical longevity (~50 years) were comparable with other methodologies. While not as extreme as the estimates from radiocarbon bomb analysis, the age-related life history traits back-calculated in the present study exceed the ages inferred from traditional vertebral counts. Because data came almost exclusively from immature individuals, these results should be interpreted cautiously; nevertheless, the estimated growth curve remains useful for aging juvenile white sharks. Overall, this study demonstrates that CMR data can produce reliable length–age estimates for white sharks, highlighting the value of data collected from non-lethal bather protection programs to study shark species.