Variation in Guiana Dolphin whistles over 10 years in Ilha Grande Bay
Guiana dolphin; acoustic repertoire; bioacoustics; cetaceans; acoustic parameters
Acoustic repertoires can vary in time scale and may present changes influenced by the creation of new social alliances and/or changes in the acoustic landscape. Thus, the objective of this work was to evaluate the changes in the acoustic parameters of the whistles obtained by the Guiana dolphin in Ilha Grande Bay over 10 years. This study uses as a basis a bank of acoustic recordings in Ilha Grande Bay from the years 2007-2008 and new recordings made in 2017-2018. To understand the temporal variation, the mean frequency, duration of whistles and emission rate in movement and foraging behavior were compared. In this study, it was identified that the emissions of this population show changes over time. These changes include an increase in maximum frequencies, little increase in minimum frequency and emission rate. These changes seem to occur in response to the fluidity of the rate of residence in the area and presence of calves evidencing the ecological importance of the area as a nursery.