Assobios emitidos em sequência por botos-cinza (Sotalia guianensis), na Baía de Guanabara, RJ

• Autor(a) principal: Lima, Bianca Rezende
• Data de Publicação: 2017
• 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/1/13857
• topic: Whistles emitted in sequences; Acoustic repertory; Contour types; Estability; Signature whistles; Assobios em sequência; Repertório acústico; Tipos de contornos; Estabilidade; Assobio-assinatura; CNPQ::CIENCIAS EXATAS E DA TERRA::OCEANOGRAFIA::OCEANOGRAFIA BIOLOGICA

Acoustic sequences are combinations of sound emissions that can have different meanings to animals. They can be found in many taxons, like cetaceans. Although studies regarding whistle sequences are still very incipient, the signature whistle hypothesis have been well developed over the years. The present study investigated whistles produced in sequence by a Guiana dolphin (Sotalia guianensis) population in Guanabara Bay. The recording system used for data collection consisted in a combination of two hydrophones and two recorders during the period of the study: a hydrophone High Tech, model HTI-96-MIN, or a C54XRS hydrophone, and a Marantz PMD 671 digital recorder with a sampling rate of 96 kHz or a Fostex FR-2 digital recorder with a sampling rate of 192 kHz. The analysis of the spectrograms was conducted with the Software Raven 1.5 (Cornell Lab of Ornithology, Ithaca, NY), with an upper limit of 96 kHz (24bits, Hann, 512 points; sample rate of 192 kHz) and 48 kHz (24bits, Hann, 512 points; recording with sample rate 96 kHz), depending on the recorder used. In addition, the different behavioral states of the groups were observed in the field and classified in: feeding, socialization or traveling. Whistles emitted in sequence were classified into distinct types due to differences in their contours due to fundamental frequency modulation. The sequences were considered when whistles with the same contour type were found immediately behind each other. The acoustic parameters start frequency, end frequency, minimum frequency, maximum frequency and frequency modulation were extracted to characterize the whistles in sequences and isolated whistles. Descriptive statistics (mean, standard deviation, coefficient of variation and median) of sequences were measured in sequences found in several years to investigate the stability of whistle types over the years. and the Mann-whitney test were realized to characterize and compare the acoustic parameters The crossing information of whistle type and individuals present in the group was done with the aim to find the sequence s emitter. Altogether, 1599 whistles found isolated and 395 whistles in sequences, totalizing in 170 sequences. Whistles in sequence represented 19,7% of analised whistles, this percentage is lower than for cetaceans. Sequences were found in every behavior, feeding is the most behavior recording and the socialization represent with the highest number of sequences proportionally. Acoustic repertory of guiana dolphin are high variability of types of whistles. Whistles in sequence showed longer durations, higher maximum frequencies and higher frequency modulations than isolated whistles, with stability over the years. So, their differentiated characteristics and stability can demostrate that they are biologically important signals. The association between the individuals and the whistles in sequences showed no evidences for the existence of signature whistles in the Baía de Guanabara s population