EST. SOBRE CETACEOS ODONTOCETES ENC. EM PRAIAS DA REGENTRE IGUAPE (SP) E A BAIA DE PARANAGUA (PR) (24 42S-25 28S) COM ESP. REF. A SOTALIA FLUVIATILIS (GERV.1853 / Study about odontocete cetaceans founded in beaches between Iguape (SP) and Baía de Paranaguá (PR) (24 graus´42´S - 25´S graus´28´S) with sécial reference of sotalia fluviatilis (Gervais, 1953) (Delphinidae).

AUTOR(ES)
DATA DE PUBLICAÇÃO

1990

RESUMO

The occurrence, morphometric and craniometric data and stomach contents of odontoceti cetaceans found in the south coast of São Paulo State and north coast of Paraná State (Ilha Comprida, Marujá and Deserta beaches) from April, 1986 to April, 1988 were analysed in this study. For the most abundant species we estimated the individual age by reading growth layers in the dentine. We found 100 animaIs belonging to 7 genera, 7 species and 3 famiIies. The first records for this region were: Delphinus delphis (n=13), Stenella frontalis (n=3). Kogia breviceps (n=1), and Globicephala macrorhynchus (n=1). The first ones for the coast of São Paulo State were: S. frontalis and G. macrorhynchus. This Iast species was also first described for the southwestern Atlantic. AlI of the species were new records for the coasts of Paraná State except S. fluviatilis. This Iast one was the most abundant species (n=58), followed by Pontoporia blainvillei (n=21). We also encountered Tursiops gephyreus (n=2) and an unidentified delfinid. There was little seasonal pattern in the total occurrence of the animals with a small increase in their abundance during the winter and summer seasons. For the most abundant species, Sotalis fluviatilis, we estimated some growth parameters using published equations which describe the interspecific relationships of these parameters. Physical maturity was considered in animals with for more dental layers. A growth curve was drawn by eye, using data obtained the from some of the above equations and data obtained from individuaIs analysed in this study, such as dental layers and total length; a growth curve by von Bertalanffys method did not fit well. The species plateau development of 5 skull functional components for this showed 6 dental layers for the attainment of adult plateau except for the feeding apparatus which stops growing at 8 dental layers. The diet of S. fluviatilis consisted mainly of demersal and superficial pelagic common fishes found in the Brazilian southeastern coast. The Sciaenidae family was the most abundant. Beaks of squids belonging to 2 or 3 especies were found in all stomach contents analysed; we also encountered shrimps in one stomach content. Stomach parasites belonging to the Anisakidae family were found in 28,6% of the stomachs with the same frequency of fish gill parasite isopods. Most of the cetaceans were probably captured accidentally with gillnets in adjacent waters of the studied beaches.

ASSUNTO(S)

cetacea boto brasil odontocete dolphin golfinho stranded cetacea encalhe sotalia fluviatilis delphinidae odontocete delphinidae brasil sotalia fluviatilis

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