Assobios de delfinídeos na costa do Estado do Rio de Janeiro: caracterização e comparação interespecífica

• Autor(a) principal: Lima, Isabela Maria Seabra de
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/13877
• topic: Whistles; Delphinids; Rio de Janeiro; Assobios; Delfinídeos; Rio de Janeiro; CNPQ::CIENCIAS EXATAS E DA TERRA::OCEANOGRAFIA::OCEANOGRAFIA BIOLOGICA

Delphinids have a diverse acoustic repertoire, in which sounds are emitted in different behavioral contexts and are important for the relationships among individuals. The acoustic signals are predominantly used for communications and are divided in two categories: burst-pulses and whistles. The present study presents comparisons amog whistles of three different species of delphinids found in the Rio de Janeiro State Coast: Stenella frontalis, Steno bredanensis e Sotalia guianensis. Three sound recording systems were used. They were composed by hydrophones HTI-96-MIN and C54XRS, and recorders PMD 671 Marantz, FOSTEX (sample rate of 96 kHz) e SONY TCD-T8 (sample rate of 48 kHz). The spectrograms were analysed in the software Raven 1.4. The whistles were classified in countour form categories and 15 acoustic parameters were measured in each of the signals. Descriptive statistic was used for the whistles of each species and these whistles were compared by the use of mean comparison tests and discriminant analysis. A total of 838 whistles were analysed. Whistles with ascending contour form of S. frontalis, S. bredanensis, S. guianensis from Guanabara Bay, Ilha Grande Bay and Sepetiba Bay corresponded to 48.1% (N=63), 40.8% (N=47), 49.8% (N=98), 63.9% (N=126) and 58.1% (N=115) of the repertoire of each group, respectively. Differences were found between whistles of S. bredanensis and S. guianensis in pratically every parameter. The greater number of similarities occurred among the whistles of different populations of S. guianensis. The total correct classification percentage was 52.4%. Whistles of S. bredanensis presented the largest correct classification score (84.3%). Whistles of S. frontalis presented correct classification percentage of 55.7% and the whistles of S. guianensis from Guanabara Bay, Ilha Grande Bay and Sepetiba Bay presented correct classification scores of 57.9%, 48.7% and 29.8%, respectively. The discriminant analysis among ascending whistles resulted in a lower correct classification percentage (49%). The variables that were considered most important to discriminate among species were: FF, 3Q, 1Q, MOD e FM. Through the use of acoustic parameters it was possible to discriminate a great number of whistles of the simpatric species, despite the overlap that exists among the variable values of the whistles of the species compared in this study.