A Novel Technique for Photo-Identification of the Fin Whale, Balaenoptera physalus, as Determined by Drone Aerial Images

Abstract

Drones have become a crucial research tool across marine environments over the past decade, being specifically useful in marine mammal research. Fin whales (Balaenoptera physalus) have been monitored feeding along the Catalan coast, Spain (NW Mediterranean), since 2014. To overcome issues such as the distance between a whale and a research vessel or the lack of distinctive dorsal fin features, an aerial identification technique was developed. It uses the fin whales’ characteristic central chevron pattern (CCP) and blaze, which are clearly visible from an overhead position. A total of 237 individual whales were identified between 2015–2022 in this study area, of which there were 35 interannual recaptures. While the dorsal fin may undergo modifications over time, the CCP and blaze patterns did not naturally alter over the years, with one whale displaying the same characteristics 8 years apart between the first and the most recent sightings. As such, this coloration pattern provides a reliable identification feature to be used for the interannual identification and population monitoring of fin whales using drones. This novel technique aims to improve and unify this species cataloguing overseas by using the CCP and blaze obtained from UAV (unmanned aerial vehicle) zenithal videos as a robust identification tool.

Targeting fin whale conservation in the North-Western Mediterranean Sea: insights on movements and behaviour from biologging and habitat modelling

“…In this context, fast-paced technological advancements and analytical frameworks developed in recent decades are key tools for reducing these current knowledge gaps. The use of unmanned aerial vehicles (UAVs; [ 7 , 8 ]), environmental DNA (eDNA; [ 9 ]), remotely sensed imagery [ 10 ] and satellite-linked telemetry [ 11 , 12 ] has been critical in this regard, particularly within marine environments where regular observation would be otherwise logistically impractical.…”

Observing Individuals and Behavior of Hainan Gibbons (Nomascus hainanus) Using Drone Infrared and Visible Image Fusion Technology

“…The authors in [8] used a drone to research the waterbird populations, ungulates, and non-human primates. Degollada et al [10] identified fin whales (Balaenoptera physalus) using a drone. The authors in [11] used a drone to identify blacknecked swans (Cygnus melancoryphus).…”

First aerial observation of Sato's beaked whales (Berardius minimus) above the Abashiri Submarine Canyon, Hokkaido, Japan

“…As has already been reported in some species, UAVs play an essential role in cetacean ecological research, including individual identification (e.g., Degollada et al, 2023), body length or body condition estimation (e.g., Aoki et al, 2021;Stewart, 2021), behavioral observation (e.g., Amano et al, 2021;Hartman et al, 2020), and biopsy and microbiome sampling (e.g., Costa et al, 2022). Compared to boat surveys, UAVs generate significantly less noise in the water, making them less threatening to whales (Christiansen et al, 2016).…”