@article {53309, title = {Monitoring noise levels and delphinid presence through autonomous acoustic in Rio de Janeiro coastal area}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1885 - 1885}, abstract = {

In order to investigate the soundscape in a Rio de Janeiro coast site, passive acoustic monitoring was conducted during two non-consecutive weeks in the summer of 2015/2016 by deploying one SM2M\ + device. The equipment recorded at a 66\% duty cycle with sample rate of 96 kHz and 36 dB gain. Third octave levels (TOLs) were calculated for all recordings through PAMGuide software. To search for delphinid presence, a band limited energy detector was employed using Raven 1.5 in a 512 Hann window, 50\% overlap. TOLs varied across frequencies and day hours. Light hours were noisier than dark hours in 25 frequency bands (MW, p\<0.01), with highest mean level being measured at 794 Hz at 06am (105.4 \± 5.4 dB re 1\μPa), and lowest mean level measured at 39.8 kHz at 01am (80.3 \± 3.7 dB re 1\μPa). A total of 281 delphinid sound emissions were detected in nine occasions, seven during week 1 and two during week 2. Seven detection events occurred during dark hours. Although more than one species of delphinid is known to occur in Rio de Janeiro coast, these results indicate a frequent nocturnal use of the area, which was only possible to observe through autonomous monitoring.

}, issn = {0001-4966}, doi = {10.1121/1.5068264}, url = {http://asa.scitation.org/doi/10.1121/1.5068264}, author = {Bittencourt, Lis and Sousa, Andr{\'e} and Bisi, Tatiana and Lailson-Brito, Jos{\'e} and Azevedo, Alexandre d.} } @article {53291, title = {Characteristics of Guiana dolphins ( Sotalia guianensis) burst-pulse sounds emitted during different surface activity rates in Rio de Janeiro{\textquoteright}s coast}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1978 - 1978}, abstract = {

Burst-pulses are still the least studied signals in delphinid acoustic repertoire. In this study, acoustic data were gathered in two Rio de Janeiro coastal bays where groups of Guiana dolphins can be found regularly. The acoustic equipment consisted of a C54XRS hydrophone (-155.8 dBV, 0.006 Hz a 203 kHz) and a Fostex digital recorder (192 kHz sampling rate). During each recording, the surface activity rate of the group was classified as being high or low. Burst-pulses were analyzed using SoundRuler software. Fifty signals were randomly selected and the values for duration (low = 143.9 \± 145.4; high = 82.2 \± 74.8), interpulse interval (low = 2.81 \± 1.92; high = 1.34 \± 1.35), number of pulses (low = 52.6 \± 55.7; high = 71.6 \± 64.5), peak frequency (low = 37.4 \± 2.5; high = 38.5 \± 3.2), and minimum frequency (low = 15.4 \± 6.5; high = 6.7 \± 5.3) were measured. Additionally, a Mann-Whitney U test compared all acoustic parameters of burst-pulses emitted during both surface activity rates. Significant differences between activity rates were found for interpulse interval (p\<0.01) and minimum frequency (p\<0.01). This scenario could indicate that some burst-pulse parameters are related to group arousal and behavior.

}, issn = {0001-4966}, doi = {10.1121/1.5068636}, url = {http://asa.scitation.org/doi/10.1121/1.5068636}, author = {Barbosa, Mariana and Bittencourt, Lis and Andrade, Luciana and Bisi, Tatiana and Lailson-Brito, Jos{\'e} and Azevedo, Alexandre d.} }