Dieta e ecologia alimentar do boto-cinza, Sotalia guianensis (Cetartiodactyla: Delphinidae) na região do banco dos Abrolhos, Costa Central do Brasil

• Autor(a) principal: Rodrigues, Vitor Leonardo Amaral
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/3163
• topic: Guiana dolphin; Feeding strategy; Prey; Boto-cinza; Estratégia alimentar; Presas; Ciências Ambientais; Golfinho - Alimentos; Cadeias alimentares (Ecologia); Peixe estuarino - Ecologia; Abrolhos, Arquipélago dos (BA) - Ecologia; 55

In the present study the diet and feeding ecology of Guiana dolphin (Sotalia guianensis) from Abrolhos Bank region was investigated by analyzing the stomach contents of 42 stranding individuals, from 2003 to 2012. The food itens were identified at the minor taxonomic level by the prey hard structures (sagittal otoliths and cephalopod beaks) and also quantified by count, size and biomass. The bony fish were the mainly food resource of Guiana dolphin, followed by cephalopods and crustaceans. The overall diet was comprised by 37 prey taxa, being 33 bony fishes, two cephalopods and two crustaceans. The mainly consumed prey taxa were I. parvipinnis, S. rastrifer, Bagre sp., Macrodon sp., T. lepturus, e Mugil sp. The ontogenetic development of Guiana dolphin seems to affect their feeding patterns, so that, prey items consumed by juvenile dolphins were smaller and their diet less diverse compared to adult ones. The diet composition even showed a seasonal pattern as follow: cutlass fish (T. lepturus), squids and the shortfin-corvina (I. parvipinnis) were most abundant in the summer; catfish (Bagre sp.) and mullet (Mugil sp.) were most common in the winter/autumn and the star drum (Stellifer sp.) and king weak fish (Macrodon sp.) were predominant during spring. This study provides evidences of Guiana dolphin being a generalist and opportunistic forager in the studied region as it showed a wide feeding spectrum, low dominance for most preys and great diet variation between the individuals. Regarding the ecological classification, the mainly prey taxa of Guiana dolphin came from benthic demersal habitats, occur over soft bottom and present some estuarine dependency. Also was observed a great contribution of soniferous fishes to diet reinforcing the hypothesis that this small cetacean use audition or even passive electroreception to detect their prey. This study provides the first description of Guiana’s dolphin diet on Abrolhos Bank region and also gives important insights on feeding ecology of this specie as like: ontogeny, seasonality, feeding strategy and individual variation.