Elevating Photo‐Identification: Aerial‐Identification Improves Re‐Sight Rates and Supports Long‐Term Monitoring of Humpback Whales

ABSTRACT Photo‐identification (photo‐ID) is a widely used, non‐invasive method for monitoring individual animals, including humpback whales ( Megaptera novaeangliae ; HBWs), and has provided valuable insights into their population dynamics, movement patterns, and social structures. Traditional identification relies on the trailing edge and ventral pigment patterns of the tail fluke (fluke‐ID); however, not all whales present their flukes, limiting identification and re‐sighting opportunities. We developed a novel aerial‐identification (aerial‐ID) approach using drone imagery to identify individual HBWs based on the arrangement of two features, tubercles (TB) and cookiecutter shark scars (CCS). Between January and March 2022, we sampled 1498 HBWs, including repeated individuals, capturing fluke‐ID images for 772 and aerial‐ID images for 1437. Fluke‐ID yielded 164 re‐sightings (76 lactating females, 88 others), while aerial‐ID yielded 372 (249 and 123, respectively), representing a 227% increase for lactating females and 40% for others. We extended this approach to a multi‐year, cross‐regional dataset (2018–2025) of 54 individuals verified with fluke‐ID. All were matched using aerial‐ID, with the longest re‐sight spanning 2737 days (6.5 years), representing the maximum interval within our study period. Aerial‐ID thus offers a powerful complement to fluke‐ID, expanding demographic coverage, increasing re‐sighting rates, and enabling long‐term, cross‐regional monitoring.