A Non-Invasive Video-Based Method for Tracking Marine Megafauna Movement: A Pilot Study Using a 24-Second Whale Shark Video from the Persian Gulf.

Abstract

Non-invasive video tracking offers a scalable, cost-effective alternative to invasive tagging for studying marine megafauna movement. However, its potential with brief footage remains underexplored. This pilot study presents a preliminary application of the method using a 24-second video of a whale shark (Rhincodon typus) near Abu Musa Island in the Persian Gulf on October 10, 2023. Due to the short duration and single-individual observation, findings are exploratory and intended to demonstrate feasibility rather than establish generalizable conclusions. Using VideoTracker software and Python tools (OpenCV, NumPy), we tracked a 4-m-long shark swimming at 5 m depth, covering 19.25 m over 24 s with speeds ranging from 0.51 to 1.16 m/s (mean 0.78 ± 0.19 m/s) and an energy expenditure of 0.66 units. The near-linear trajectory (sinuosity 1.07) suggests steady cruising, consistent with efficient locomotion (Gleiss et al. 2011) and prior speed-based movement analyses (Sleeman et al. 2010). This proof-of-concept highlights the potential of video-based tracking in resource-limited contexts and encourages its further refinement for broader ecological applications.