A preliminary multi-country assessment of river dolphin acoustic detections using PODs in South America

River dolphins (Sotalia fluviatilis and Inia spp.) rely on sound for navigation, foraging, and
communication, making passive acoustic monitoring a promising research tool. We present
a preliminary assessment of the PODs detections across five South American countries. A
total of 486,816 minutes of recordings were collected, with 18% showing positive detections.
Detection rates varied among sites and were generally higher in confluences, lakes, and in a dam
reservoir than in other habitats. Although PODs cannot reliably distinguish among sympatric
species and may miss weak signals, our results show that they can provide useful information
on dolphin occurrence in remote freshwater systems, supporting their use as a complementary
tool for broad-scale monitoring.

The work was carried out in Bolivia, Brazil, Colombia, Peru, and Venezuela – between 2022 and 2024.