DOI: 10.5061/dryad.d2547d88r
title: Behavioral response of delphinids to sonar - supporting acoustic data

description: Oceanic delphinids around naval operations are regularly exposed to
 intense military sonar broadcast within the frequency range of their
 hearing. However, empirically measuring the impact of sonar on the
 behavior of highly social, free-ranging dolphins is challenging.
 Additionally, baseline variability or the frequency of vocal
 state-switching among social oceanic dolphins during undisturbed
 conditions is lacking, making it difficult to attribute changes in vocal
 behavior to anthropogenic disturbance. Using a network of drifting
 acoustic buoys in controlled exposure experiments, we investigated the
 effects of mid-frequency (3-4 kHz) active sonar (MFAS) on whistle
 production in short-beaked (Delphinus delphis delphis) and long-beaked
 common dolphins (Delphinus delphis bairdii) in southern California. Given
 the complexity of acoustic behavior exhibited by these group-living
 animals, we conducted our response analysis over varying temporal windows
 (10 min – 5 s) to describe both longer-term and instantaneous changes in
 sound production. We found that common dolphins exhibited acute and
 pronounced changes in whistle rate in the 5 s following exposure to
 simulated Navy MFAS. This response was sustained throughout sequential
 MFAS exposures within experiments simulating operational conditions,
 suggesting that dolphins may not habituate to this disturbance. These
 results indicate that common dolphins exhibit brief yet clearly detectable
 acoustic responses to MFAS. They also highlight how variable temporal
 analysis windows – tuned to key aspects of baseline vocal behavior as well
 as experimental parameters related to MFAS exposure – enable the detection
 of behavioral responses. We suggest future work with oceanic delphinids
 explore baseline vocal rates a-priori and use information on the rate of
 change in vocal behavior to inform the analysis time window over which
 behavioral responses are measured.
description: # Behavioral response of delphinids to sonar - Supporting acoustic data
 This data set contains
 information on detected whistle counts from acoustic recordings collected
 as part of a research project investigating the potential responses of two
 dolphin subspecies to simulated mid-frequency active sonar sounds.
 Whistles were detected using the Whistle and Moan Detector in the program
 Pamguard. The associated zip file contains a single .csv for each CEE,
 with the filename indicating the CEE year and number (e.g.,
 CEE2021_01_closestBuoyWhistles_1sec_20k.csv). **Column headers:** dateTime
 = date and time in local timezone (PST or PDT) period = experimental
 period, either 'pre' for pre-exposure, 'exp' for
 exposure, and 'post' for post-exposure period numWhistles =
 number of detected whistles that start within the 1 second specified in
 the dateTime column. NaNs indicate periods where no buoys were within the
 1600 m distance threshold durWhistles = sum of durations of the detected
 whistles that start within the 1 second specified in the dateTime column.
 NaNs indicate periods where no buoys were within the 1600 m distance
 threshold buoy = closest buoy from which the detected whistle counts were
 taken buoyDist = distance in meters between the closest buoy and the focal
 animals. Buoy location was tracked via buoy-mounted GPS, and focal animal
 location was taken from the UAS-mounted GPS. Distances are given every
 minute, with NaNs for each second where a distance is not available
 buoyDistInterp = distance in meters between the closest buoy and the focal
 animals, interpolated to every 1-second resolution using linear
 interpolationDescription of the data and file structure