Citizen science as a tool to assess cetacean diversity in the Atacama Desert coast

An understanding of the fine-scale distribution, diversity, and population trends of endangered cetacean species threatened by anthropogenic activities is key for their conservation. In remote places such as the coastline of the Atacama Desert in Northern Chile, research focused on cetacean species is often limited by funding, and personnel. However, scientific interest from local citizens could be an alternative and useful tool to obtain valuable information on cetaceans. Here, we assess the power of citizen science as a tool to determine cetacean species richness, group size, behaviour, seasonality and conservation threats in Northern Chile by undertaking training workshops for local citizens on cetacean species identification and data gathering. A total of 24 citizen scientists reported 495 cetacean sightings during the period between 2013 and 2020, with a total of 19 cetacean species observed (6 mysticetes and 13 odontocetes). One bay (Mejillones Bay) dominated most cetacean sightings (73%) in the study area (Antofagasta region). Seven cetacean species were more frequently observed year-round: Balaenoptera physalus, Megaptera novaeangliae, Grampus griseus, Tursiops truncatus, Lagenorhynchus obscurus, Delphinus capensis and Phocoena spinipinnis. Other species were either opportunistically observed or were rare stranded species. Four species of cetaceans, B. physalus, D. capensis, L. obscurus, and P. spinipinnis were observed mostly traveling (43%) and feeding (37%), indicating that the study region is an important feeding area. Twelve cetacean species were reported stranded, and citizen scientists identified 3 species of cetaceans entangled in fishing nets. This study shows the potential of citizen science for providing information on cetacean richness and threats in remote locations such as the South East Pacific. This approach may improve knowledge on fine-scale cetacean distribution for regions that are sparsely populated and have limited research activity.