Journal Article
Seasonal Occurrence and Behavior of an Endangered Franciscana Dolphin ( Pontoporia blainvillei pukusi ) Population
Jonathas Barreto; Amanda Di Giacomo; Daniel Venturini; Federico Sucunza; João Batista Teixeira; Jordana Borini Freire; Lorena Nascimento; Luciano Cajaíba; Nelson Barcelos; Thamires Bride Ventura; Agnaldo Silva Martins
Marine Mammal Science · Vol. 42, Issue 2 · 2026
Abstract
The franciscana dolphin ( Pontoporia blainvillei ) is a threatened cetacean whose northernmost population (Franciscana Management Area Ia)—part of the recently described subspecies P. b. pukusi— faces significant anthropogenic pressures, including impacts from a major mining dam collapse. However, fundamental data on its seasonal ecology remain scarce. This study aimed to investigate the seasonal variation in occurrence, group composition, and behavior of this isolated population. Over 5 years (2018–2023) we conducted 1440 systematic drone surveys across three coastal sites in Espírito Santo, southeastern Brazil. Our results revealed a significant seasonal pattern, with franciscana sightings, particularly of calves, being more frequent during the summer ( p