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A review on the life history parameters and threats to bottlenose dolphins in two estuaries of southern Brazil
Pedro Fruet, Fabio Daura-Jorge, Rodrigo Genoves, Carolina Bezamat, Juliana Di Tullio, Paulo Simoes-Lopes, Eduardo Secchi
International Whaling Commission
In this work we summarized the updated available information on the population ecology and threats faced by two estuarine Management Units (MUs) of bottlenose dolphins in Southern Brazil: Laguna (LGN) and Patos Lagoon Estuary (PLE). Main data presented were extracted from published papers and complemented by some new information provided by personal observations from researchers conducting ongoing long-term monitoring programs. Both MU’s share similar unprecedented low levels of genetic variation, life history patterns and low abundance, despite representing the largest population sizes for the species along the coast of southern Brazil and Uruguay. These MUs are experiencing increased rates of human-related mortalities, especially due to bycatch in gillnets and facing considerable coastal habitat degradation. Bottlenose dolphins from Laguna, in particular, have being affected by a chronic dermal infection, with evidence of an increase in the number of affected animals in recent years. We call the attention to the high chances of population decline in the future due their small population sizes and stochastic events, high degree of residency and the increasing incidence of mortality as consequence of unregulated fisheries and other human activities in these areas.