Tiger
Shark
Measurements
We collect size measurements of free swimming tiger sharks since 2022 using laser photogrammetry. This non-invasive method enables us to track size and growth over time. Up to date, we have collected size measurements of over 100 different tiger shark individuals.
Laser Photogrammetry
The laser photogrammetry system uses two parallel lasers mounted a fixed distance apart on an underwater camera housing. When the lasers project two dots onto the shark’s body, the known distance between the dots creates a scale reference in each frame. By capturing still images or video as the shark passes, we can calculate the length and body proportions with high accuracy.
This method avoids physical handling, allows repeated measurements of the same individuals over time, and supports growth monitoring, size-structure assessments, and long-term population studies in a fully welfare-friendly way.
calibration
Before collecting field data, the camera-laser system is calibrated using an underwater checkerboard plate. The checkerboard’s known pattern allows us to correct lens distortion and verify the exact pixel-to-distance ratio at different distances. This ensures that all subsequent shark measurements are accurate and consistent across dives.
