Use of drones for the creation and development of a photographic identification catalogue for an endangered whale population

Abstract

Photographic identification is increasingly being used as a cost-effective and minimally invasive method to monitor species, which is of particular importance for endangered populations that are vulnerable to intrusive research methods. The purpose of our study was to collect photographs of an endangered population of beluga whales ( Delphinapterus leucas (Pallas, 1776)) in Cumberland Sound, Nunavut, Canada, for use in photographic identification. Rather than pursuing the whales with boats to collect photographs, drones were used to minimize disturbance. We analyzed drone photographs from 2017 to 2019 for distinctive markings on the whales, which were used to develop a photographic identification catalogue. In total, 93 individuals were identified, with 24 resightings of marked individuals over the survey period. Approximately 43.4% (standard error 3.3%) of the adult beluga population was uniquely marked. The beluga population has been harvested at a rate of 41 whales per year, not including struck and lost, since 2002. The markings were from unknown origins (61%), scars/wounds from gunshots (27%), anthropogenic or predatory given the size and severity (11%), or a satellite tag (1%). The continuation of the photographic identification program will allow for the estimation of important population demographics, such as abundance and calving interval, which are important parameters for population conservation and management.