Initial data set of acoustic encounters
We are currently processing the initial data set of acoustic encounters, which contains regular and slow clicks. Since the towed array data contain variable noise levels (primarily due to noise from water flow and ship propellers), we are using a combination of automated click detectors with manual validation to annotate all echolocation clicks within each acoustic encounter. So far, we have analyzed a total of 17 encounters lasting between 2.4 – 120.5 minutes (mean = 64.3 minutes) and total clicks ranging from 23-9101 clicks per encounter (mean = 1710 clicks) (Figure 1). Preliminary click rates range from 0.05 – 1.78 clicks per second (Figures 2 & 3), with longer interclick interval (>10 s) giving insight on the proportion of time animals are quiet within an encounter event (Figure 4). We will continue to update these results as more acoustic encounters are analyzed.
We have also determined that some acoustic encounters have much higher noise levels depending on the towed array used, generally differing from year to year. Noise measurements for all acoustic encounters will be calculated to characterize the overall background noise to assess whether all acoustic encounters can be considered together or should be separated based on noise, which may impact detection performance.
