Predicting the breeding hotspots of the southern right whale, Eubalaena australis (Cetartiodactyla: Mysticeti), along the southern Brazilian coastline

Abstract

To predict the potential breeding hotspots of southern right whales in southern Brazil, we used a Maxent model with a “presence-only” dataset. The dataset was obtained from a systematic aerial survey and public records of the Programa de Monitoramento de Cetáceos da Bacia de Santos and Sistema de Apoio ao Monitoramento de Mamíferos Marinhos. Because of spatial autocorrelation, 528 records out of 3028 were used in the modelling process. The explanatory variables used in the models were coastal distance, linearity, slope and substrate type. The models were created separately for unaccompanied adults (Ad) and mother-calf pairs (Fe). Both models showed good accuracy according to their area under the curve values (Ad=0.974; Fe=0.958). Coastal distance was the most relevant explanatory variable for the unaccompanied adult model (54%), whereas coastal linearity was more relevant for the mother-calf pair model (82%). The estimated area for mother-calf pairs was more restricted to coastal areas than that for unaccompanied adults, possibly owing to the high number of shelter areas for calves near the coast. This is the first study to predict the potential breeding hotspots of southern right whales in Brazil and its results will allow for a more directed management of these whales and provide further research opportunities.