Dieta do boto-cinza (Sotalia guianensis Van Benédén, 1864) (Cetacea: Delphinidae) na Baía de Sepetiba (RJ) / Diet of the guiana dolphin (Sotalia guianensis Van Benédén, 1864) (Cetacea: Delphinidae) in Sepetiba Bay (RJ)

AUTOR(ES)

Ana Carolina Pires de Souza Araujo

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

27/02/2012

RESUMO

The Guiana dolphin (Sotalia guianensis, Van Benédén, 1864) is a small cetacean of the Delphinidae family. The species occurs on coastal waters from South and Central America, in estuarine environments, bays and protected areas. This study aims to characterize Guiana dolphin feeding habits and to investigate variation in diet related to sex age class and season, in Sepetiba Bay (RJ). Stomach contents of 76 S. guianensis, stranded between 2005 and 2011, were analysed. Food items found in the stomachs (otoliths, fish bones, cephalopod beaks, crustacean structures) were identified based on identification guides and one reference collection. Some measurements of the prey remains were used to estimate the length and weight of preys using regression equations specific for each prey species. Dolphin sample was gathered into adult males, adult females and juveniles. Season was defined as hot/wet season (Oct-Apr) and cold/dry (May-Sep). A total of 1800 prey were found, including 23 species of teleosts, four species of cephalopods and three species of crustaceans. Guiana dolphin in Sepetiba Bay had a typically piscivorous diet. The index of relative importance (IRI) showed that Cetengraulis edentulus; Micropogonias furnieri; Mugil spp.; Chloroscombrus chrysurus; Cynoscion jamaicensis; Stellifer sp.; e Sciadeichthys luniscutis were the seven most important species. Among cephalopods, the squid Dorytheutis plei was the most important. This study indicates that the Guiana dolphin has intra-specific variations in the diet between adult females, adult males, and young and seasonal variations in the composition of its diet. Diet composition suggests that S. guianensis feeds into Sepetiba Bay and along coastal adjacent waters.

ASSUNTO(S)

hábito alimentar oceanografia biologica cetacea cetacea sotalia guianensis cetáceo sepetiba, baía de (rj) - teses sotalia guianensis feeding habitat

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