Four decades of research on distribution and abundance of the Bolivian river dolphin Inia geoffrensis boliviensis

Abstract

The Bolivian river dolphin, known locally as the bufeo, is one of 4 species of river dolphin in South America. Endemic to the upper basin of the Madeira in the Bolivian Amazon region, the species is categorized as Endangered on the IUCN Red List. This article provides information related to the geographic distribution of the species, and a review of the studies of its abundance that have been conducted in Bolivia since the 1970s. We discuss the surveys, the analysis methods used in the different studies, and the ways in which these methods might influence the population estimates. We found 63 population abundance estimates for the Bolivian river dolphin across 17 reviewed publications. These studies report relative abundance data for rivers that range from 0.2 to 2.81 bufeos km -1 , and density ranges from 0 to 7.59 bufeos km -2 . The information presented here reflects the knowledge of the population size of the species in Bolivia obtained over 4 decades, and will be useful for developing conservation strategies and as a tool for decision makers.