01844nas a2200193   4500008004100000022001400041245011000055210006900165260001600234300001600250490000800266520121600274100002101490700001801511700001801529700002501547700002701572856005101599       2018                        eng d  a0001-496600aMonitoring noise levels and delphinid presence through autonomous acoustic in Rio de Janeiro coastal area0 aMonitoring noise levels and delphinid presence through autonomou  cJan-09-2018  a1885 - 18850 v1443 a<p>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&thinsp;+ 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&lt;0.01), with highest mean level being measured at 794 Hz at 06am (105.4 &plusmn; 5.4 dB re 1&mu;Pa), and lowest mean level measured at 39.8 kHz at 01am (80.3 &plusmn; 3.7 dB re 1&mu;Pa). 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.</p>
1 aBittencourt, Lis1 aSousa, André1 aBisi, Tatiana1 aLailson-Brito, José1 aAzevedo, Alexandre, d.  uhttp://asa.scitation.org/doi/10.1121/1.5068264