Abundance estimation of franciscana dolphins by means of aerial surveys in Buenos Aires Province, Argentina
Enrique A. Crespo, Magdalena Arias, Nicol?s Sueyro, M. Florencia Grandi and Mariano A. Coscarella
Between October 11 and 16, 2019, and March 12 and 14, 2022, 9 flights were made on the coast of the province of Buenos Aires in meteorological conditions that allowed the sighting of several species of cetaceans. The two series of surveys (2019-2022) were carried out separately due to the covid-19 pandemic. In particular for 2019, 41 sightings of Franciscana dolphins (Pontoporia blainvillei) were made, totaling 68 individuals. For the 2022 survey, 55 sighting were made comprising 80 franciscanas. In addition, several herds of common and dusky dolphins were observed, some very numerous. The abundance of Franciscana would preliminary give a figure of 19252 dolphins if we consider the estimation obtained in 2022 plus 5896 dolphins estimated in 2004 for the southern areas, roughly 20000 individuals considering those in deeper waters beyond the 30 meters isobath.