A dorsal-fin photo-identification technique paired with a non-invasive parallel laser photogrammetry technique was used to non-invasively identify individual Sphyrna mokarran over time. Based on the data collected over a duration of 59 days, 16 different S. mokarran (mean ± s.d. pre-caudal length: 220·82 ± 13·66 cm; mean ± s.d. cephalofoil width: 71·38 ± 7·94 cm) were identified using dorsal-fin photo-identification, with a mean ± s.d. shark re-sighting frequency of 4·05 ± 3·06 at-sea days. The results illustrate a high S. mokarran sighting rate and therefore, the utilization of parallel laser photogrammetry and dorsal-fin photo-identification may be a plausible multi-year approach to aid in non-invasively determining the growth rate and inter-annual site fidelity of these animals.
- Life-history characteristics
- Non-invasive measurements