Photo-identification: an effective tool to study Burmeister’s porpoises

Abstract

Photo-identification of cetaceans has been used for species with distinctive markings but has not been applied frequently to those with less conspicuous natural features or cryptic behavior, such as Burmeister’s porpoise (Phocoena spinipinnis). This study assessed the efficacy of photo-identification as a research tool for studying Burmeister’s porpoises, based on 28 dedicated surveys in the Beagle Channel, Argentina, conducted during May 2018–January 2020. In total, 386 photographs were utilized, and eight different types of marks were considered for individual identification. Wounds were the most frequently observed, followed by mottling, pigmentation patches, notches, and scars. Forty-eight individuals had reliable marks, five individuals were observed on two occasions and one individual was observed three times. The results of this study demonstrate the reliability of markings and the effectiveness of photo-identification for studying Burmeister’s porpoises, highlighting its value for long-term monitoring and for improving the understanding of population dynamics.