Abundance estimates of franciscana dolphins (Pontoporia blainvillei): a review and future recommendations
Alexandre Zerbini, Artur Andriolo, Marta Cremer, Enrique Crespo, Daniel Danilewicz, Camila Domit and Federico Sucunza
International Whaling Commission
Abundance estimates of franciscana dolphins are compiled to assist the IWC Scientific Committee with the review of the status of the species. A total of 12 estimates are available for five franciscana management areas (FMA Ia, Ib, II, III and IV) and for at least one likely isolated population in Babitonga Bay. In FMA Ia, Ib and II, and Babitonga Bay estimates are believed to encompass the known range of the population. For FMA III and IV, estimates are only partial because relatively large portions of the management areas have yet to be surveyed. This document also presents a summary of correction factors computed to account for availability, perception and group size bias in abundance estimates of franciscanas. Recommendations for future work and summaries of the abundance surveys and estimation procedures, following a format recently agreed by the IWC SC in 2019, are also provided.