DOI: 10.5061/dryad.9s4mw6mq0
title: Data from: Vocal signatures affected by population identity and environmental sound levels

description: Passive acoustic monitoring has improved our understanding of vocalizing
 organisms in remote habitats and during all weather conditions. Many
 vocally active species are highly mobile, and their populations overlap.
 However, distinct vocalizations allow the tracking and discrimination of
 individuals or populations. Using signature whistles, the individually
 distinct calls of bottlenose dolphins, we calculated a minimum abundance
 of individuals, characterized and compared signature whistles from five
 locations, and determined reoccurrences of individuals throughout the
 Mid-Atlantic Bight and Chesapeake Bay, USA. We identified 1,888 signature
 whistles in which the duration, number of extrema, start, end, and minimum
 frequencies of signature whistles varied significantly by site. All
 characteristics of signature whistles were deemed important for
 determining from which site the whistle originated and due to the distinct
 signature whistle characteristics and lack of spatial mixing of the
 dolphins detected at the Offshore site, we suspect that these dolphins are
 of a different population than those at the Coastal and Bay sites.
 Signature whistles were also found to be shorter when sound levels were
 higher. Using only the passively recorded vocalizations of this marine top
 predator, we obtained information about its population and how it is
 affected by ambient sound levels, which will increase as offshore wind
 energy is developed. In this rapidly developing area, these calls offer
 critical management insights for this protected species.
description: Acoustic data were collected between 2016 at 2018 at sites 1, 2,
 and 5 were located 12, 31, and 64 km east of Ocean City, Maryland, USA,
 respectively. Water depths at these sites ranged from approximately 20 –
 42 m, and the acoustic recording instruments were deployed approximately 1
 m above the ocean floor using bottom-anchored moorings.
 Ambient sound levels were calculated in MATLAB (MathWorks,
 Natick, Massachusetts, USA) as the relative broadband (up to 24 kHz, given
 the sampling rate of 48 kHz) root mean square sound pressure level (SPL;
 dB re 1µPa root-mean-square (rms)) during the recording in which the
 signature whistle occurred (two or five minutes in duration).
 PAMGUARD Whistle and Moan Detector was utilized to determine
 hours with possible dolphin presence. These hours were then manually
 searched for signature whistles with high signal-to-noise ratios.
 Signature whistles were manually identified using the SIGID criteria -in
 which the same whistle repeated in a pattern of two or more whistles
 within 1–10 s of one another and with a minimum length of 0.2 s. Whistle
 contours (shape of the whistle) were obtained using Beluga software (https://synergy.st-andrews.ac.uk/soundanalysis) within MATLAB (Math-Works, Natick, Massachusetts, USA). Whistles with low signal-to-noise ratio or abundant non-linear features that obscured the shape of the whistle could not be included in the analysis. For each whistle, manual measurements were taken in Raven Pro 2.0 Interactive Sound Analysis Software (Cornell Lab of Ornithology, Center for Conservation Bioacoustics, Ithaca, New York, USA) of the duration, start, end, maximum, minimum, and delta frequencies (maximum minus minimum frequency), and number of local extrema (e.g. local minima and maxima) including the start and end of the whistle.
description: # **Vocal signatures affected by population identity and environmental
 sound levels**
 [https://doi.org/10.5061/dryad.9s4mw6mq0](https://doi.org/10.5061/dryad.9s4mw6mq0) Acoustic data were collected between 2016 at 2018 at sites 1, 2, and 5 were located 12, 31, and 64 km east of Ocean City, Maryland, USA, respectively. Water depths at these sites ranged from approximately 20 – 42 m, and the acoustic recording instruments were deployed approximately 1 m above the ocean floor using bottom-anchored moorings. Ambient sound levels were calculated in MATLAB (MathWorks, Natick, Massachusetts, USA) as the relative broadband (up to 24 kHz, given the sampling rate of 48 kHz) root mean square sound pressure level (SPL; dB re 1µPa root-mean-square (rms)) during the recording in which the signature whistle occurred (two or five minutes in duration). PAMGUARD Whistle and Moan Detector was utilized to determine hours with possible dolphin presence. These hours were then manually searched for signature whistles with high signal-to-noise ratios. Signature whistles were manually identified using the SIGID criteria -in which the same whistle repeated in a pattern of two or more whistles within 1–10 s of one another and with a minimum length of 0.2 s. Whistle contours (shape of the whistle) were obtained using Beluga software ([https://synergy.st-andrews.ac.uk/soundanalysis](https://synergy.st-andrews.ac.uk/soundanalysis)) within MATLAB (Math-Works, Natick, Massachusetts, USA). Whistles with low signal-to-noise ratio or abundant non-linear features that obscured the shape of the whistle could not be included in the analysis. For each whistle, manual measurements were taken in Raven Pro 2.0 Interactive Sound Analysis Software (Cornell Lab of Ornithology, Center for Conservation Bioacoustics, Ithaca, New York, USA) of the duration, start, end, maximum, minimum, and delta frequencies (maximum minus minimum frequency), and number of local extrema (e.g. local minima and maxima) including the start and end of the whistle.  ## **Description of the data and file structure** Signature whistle characteristics: * AllChars_211025_Upload: Whistle characteristics for all signature whistles (n=357) used in the signature whistle characteristic analysis. Columns include: ID, Region, Filename, Start.freq, End.freq, Min.freq, Max.freq, Delta.freq, Duration, Extrema, sqrtStart.freq, sqrtEnd.freq, sqrtDelta.freq, logDuration, logExtrema, sqrtMin.freq, sqrtMax.freq. Sqrt indicated squareroot of the metric and log indicates that the log of the value was taken. Characteristics of the matched whistle subset: * MatchedSW_Chars_210927_FinalMatchUpload: Whistle characteristics for the subset of signature whistles (n=103) that reoccurred at different sites or times. Columns include: Index (of the pair), WhisNum (whistle number within the match), SiteNum, Filename, Region, Startfreq, Endfreq, Minfreq, Minfreq, Maxfreq, Deltafreq, Duration, Extrema, SPLrms. Freq indicates frequency (measured in Hz) and SPLrms indicates the sound pressure level (SPL) measured as root mean square (rms) measures in dB. Catalog of all matched whistles in the study area: * MatchedWhistles_210624_Chron_Upload_SiteNum: Catalog of all matched signature whistle (n=201) information. The first column title is “New Whistle” and for each matched signature whistle, the site, date, and file name for each whistle are included. Sound levels calculated for all recording periods: * SoundLevel_Dates_210927_T1C0Gain: Sound levels for all recording periods. SPLrms indicates the sound pressure level (SPL) measured as root mean square (rms) measures in dB. \------------------------------------------- **Variables:** Index: Identifier for each signature whistle or signature whistle pair WhisNum: whistle number within the match SiteNum: Site identifier Filename: File from which the signature whistle originated Region: Offshore, Chesapeake Bay, or Inshore region Startfreq (or Start.freq): Start frequency (Hz) of signature whistle Endfreq (or End.freq): End frequency (Hz) of signature whistle Minfreq (or Min.freq): Minimum frequency (Hz) of signature whistle Maxfreq (or Max.freq): Maximum frequency (Hz) of signature whistle Deltafreq (or Delta.freq): Delta frequency (maximum minus minimum; Hz) of signature whistle Duration: Duration (seconds) of signature whistle Extrema: Number of extrema (maxima or minima) of signature whistle SPLrms: Sound pressure level root mean square (dB) DateTime: Date and time of signature whistle Site: Site identifier (Sites 1-5) sqrtStart.freq: Square root of value of start frequency (Hz) of signature whistle sqrtEnd.freq: Square root of value of end frequency (Hz) of signature whistle sqrtDelta.freq: Square root of value of end frequency (Hz) of signature whistle logDuration: Log of value or duration (s) of signature whistle logExt: Log of number of extrema (maxima or minima) of signature whistle sqrtMin: Square root of value of minimum frequency (Hz) of signature whistle sqrtMax: Square root of value of maximum frequency (Hz) of signature whistle New whistle match cat: Matched whistle category \[#] sighting site: Site at which the signature whistle was recorded \[#] sighting date: Date on which the signature whistle was recorded \[#] sighting contour name: Identifying contour name from Beluga software