Diversity and distribution of cetaceans in the Republic of Palau

Abstract

Context Until recently, very little was known about the species diversity and occurrence of cetaceans in the Republic of Palau. A dedicated scientific investigation into the occurrence and distribution of island associated cetaceans in Palau was conducted in 2012 and 2013. Aims The aim of this project was to investigate the diversity and distribution of cetaceans in Palau to inform management and build local capacity in cetacean science. Methods Following a feasibility study in 2010, a vessel-based visual and acoustic line transect survey was conducted in 2012, covering a survey area of 4319 km2. The survey was repeated and expanded in 2013 using aerial methods. Additionally, small boat work was conducted in areas with high cetacean density to obtain genetic, acoustic, and photographic samples. In 2019, a vessel-based visual and acoustic survey of the Southwest Islands was conducted. Key results By combining the survey results with anecdotal sightings, a cetacean species inventory for Palau was established. The presence of 15 species was confirmed, while four species were identified as probably present and three as likely. Conclusions Survey results contributed to the management of cetaceans in the Palau Marine Mammal Sanctuary. The surveys raised local interest in cetaceans and, through public outreach and training, precipitated advancements in capacity building for cetacean management, along with a baseline for ongoing monitoring. Implications This study provided the first systematic, scientific investigation using multiple survey methods into the occurrence and distribution of cetaceans in Palau, highlighting the importance of conserving cetacean populations in this region.