Data from: Low-frequency temporary threshold shift not observed in spotted or ringed seals exposed to single air gun impulses
Data files
May 05, 2026 version files 43.78 KB
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raw_TTS_data_unformatted.xlsx
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raw_TTS_data.xlsx
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README.md
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Abstract
Underwater hearing thresholds were measured at 100 Hz in trained spotted (Phoca largha) and ringed seals (Pusa hispida) before and immediately following voluntary exposure to impulsive noise from a seismic air gun. Auditory responses were determined from psychoacoustic data and behavioral responses were scored from video recordings. Four successive exposure conditions of increasing level were tested, with received unweighted sound exposure levels from 165 to 181 dB re 1 μPa2 s and peak-to-peak sound pressures from 190 to 207 dB re 1 μPa. There was no evidence that these single seismic exposures altered hearing—including in the highest exposure condition, which matched previous predictions of temporary threshold shift (TTS) onset. Following training at low exposure levels, relatively mild behavioral responses were observed for higher exposure levels. This demonstrates that individuals can learn to tolerate loud, impulsive sounds, but does not necessarily imply that similar sounds would not elicit stronger behavioral responses in wild seals. The absence of observed TTS confirms that regulatory guidelines (based on M-weighting) for single impulse noise exposures are conservative for seals. However, additional studies using multiple impulses and/or higher exposure levels are needed to quantify exposure conditions that do produce measurable changes in hearing sensitivity.
Dataset DOI: 10.5061/dryad.v41ns1sbr
Description of the data and file structure
To evaluate the residual effects of underwater noise on pinnipeds, hearing thresholds were obtained for four seal subjects before and after voluntary exposure to impulsive noise from a seismic air gun. Behavioral psychophysical methods were used to cooperatively evaluate hearing. Temporary threshold shift (TTS) was measured as the difference between a seal's pre-exposure hearing threshold and the subsequent post-exposure hearing threshold at 100 Hz, approximately ½-octave above the maximum energy in the received impulse.
Four successive exposure conditions of increasing level were tested, denoted as C1, C2, C3, and C4. These exposure conditions were associated with received unweighted sound exposure levels from 165 to 181 dB re (1 μPa)2 s and peak-to-peak sound pressures from 190 to 207 dB re 1 μPa.
The data included here comprise raw TTS measurements and behavioral scores associated with each individual exposure and control (no-noise) sequence during testing.
Additional details are provided in the associated manuscript text.
Files and variables
File: raw_TTS_data.xlsx
Description: Raw data are presented for each noise exposure and control sequence conducted throughout this study. These data support the presentation of summarized data in Figure 3 of the primary manuscript.
Variables
- Species: Phoca largha (spotted seal) or Pusa hispida (ringed seal)
- Sex: Male or female
- Age: Age of the subject during testing (in years)
- Subject: seals AMAK, NATCHECK, NAYAK, or TUNU
- Exposure date: YYYY-MM-DD of test sequence
- Exposure condition: one of four successive noise exposure conditions of increasing level (C1, C2, C3, C4) or a no-noise condition (CONTROL)
- Exposure number: ordinal position of the exposure sequence within a condition
- Noise exposure level (pk-pk): noise exposure level in absolute terms (unweighted peak-to-peak sound pressure, dB re 1 μPa); this is entered as "n/a" (not applicable) for control (no-noise) sessions
- Noise exposure level (SEL): noise exposure level expressed as unweighted sound exposure level (SEL, dB re (1 μPa)2 s); this is entered as "n/a" (not applicable) for control (no-noise) sessions
- Pre-exposure threshold at 100 Hz (dB re 1 μPa): hearing threshold obtained just prior to noise exposure
- Post-exposure threshold at 100 Hz (dB re 1 μPa): hearing threshold obtained immediately following noise exposure
- Threshold Shift (dB): difference between pre-exposure and post-exposure hearing thresholds in decibels
- Behavioral response score: score assigned based on video review of the subject’s behavior during and immediately following each exposure event; 0 indicated no detectable change in stationing behavior, 1 indicated a just-detectable change (slight movement without breaking contact with the station), 2 indicated a momentary change (movement of the subject’s head from the station), 3 indicated that the subject moved less than one-half of a body-length from the station and returned, 4 indicated that the subject moved greater than one-half of a body-length from the station and returned, and 5 indicated that the subject’s stationing behavior was disrupted and did not recover
File: raw_TTS_data_unformatted.xlsx
Description: Same as raw_TTS_data.xlsx with formatting removed.