McKnight Brantley (reasontarget1)

This paper found that, for a given ITD sensitivity, hearing-impaired listeners experienced less BRM than normal-hearing listeners, suggesting that binaural TFS sensitivity can account for only a modest portion of the BRM deficit in hearing-impaired listeners. However, substantial individual variability was observed.Behavioral guidance systems are commonly used in freshwater fish conservation. The biological relevance of sound to fish and recorded responses to human-generated noise supports the viability of the use of acoustics as an effective stimulus in such technologies. Relatively little information exists on the long-term responses and recovery of fish to repeated acoustic exposures. In a controlled laboratory study, the response and tolerance of Eurasian minnow (Phoxinus phoxinus) shoals to tonal signals (150 Hz of 1 s pulse duration) differing only in temporal characteristics ("continuous," "slow," "intermediate," or "fast" pulse repetition rate) were investigated. In comparison to independent control groups, fish increased their mean group swimming speed, decreased inter-individual distance, and became more aligned in response to the onset of all four acoustic treatments. The magnitude of response, and time taken to develop a tolerance to a treatment differed according to pulse repetition rate. Groups were found to have the greatest and longest lasting response to tone sequences tested in this study when they were pulsed at an intermediate rate of 0.2 s-1. This study illustrates the importance of understanding the response of fish to acoustic signals, and will assist toward the development of longer-term effective acoustic guidance systems.Passive acoustics is used to monitor the threatened St. Lawrence estuary beluga between 2007 and 2017 from a site downstream of the beluga summer habitat. Acoustic metrics of presence and occurrence based on beluga acoustic band activity (BABA) are extracted by a dedicated algorithm adapted for the shipping noise from the St. Lawrence Seaway. A formal optimization process is used to set the algorithm parameters. Results evidence a year-round occurrence of belugas in the region, seasonal and diel patterns, and significant inter-annual variations. This study shows how passive acoustics methodology can be applied to monitor a loquacious species over multi-year periods in a shipping-noise-dominated environment, in order to understand its use of the habitat over the continuum of ecologically significant time scales.Ambient noise was recorded continuously for 9 months by two horizontal arrays deployed in shallow water with a horizontal separation of approximately 0.5 km. Stable empirical Green's functions (EGFs) were extracted from ambient noise correlations between the two arrays. The EGFs have three distinct envelopes which correspond to the head waves, direct waves, and surface-reflected waves. The arrival time of the head wave was almost constant with season. Corresponding simulations were carried out, and implied that the relatively small penetration depth of heat flow is the main reason for the seasonally-invariant head wave speed.As part of a series of studies to determine frequency-dependent susceptibility to temporary hearing threshold shifts (TTS), two female harbor seals (F01 and F02) were exposed for 60 min to a one-sixth-octave noise band centered at 40 kHz at mean sound pressure levels ranging from 126 to 153 dB re 1 μPa [mean received sound exposure level (SEL) range 162-189 dB re 1 μPa2s]. TTSs were quantified at 40, 50, and 63 kHz within 1-4 min of the exposure for F02 and within 12-16 min of the exposure for F01. In F02, significant TTS1-4 (1-4 min post exposure) occurred at 40 kHz with SELs of ≥183 dB re 1 μPa2s and at 50 kHz with SELs of ≥174 dB re 1 μPa2s. At 63 kHz, TTS1-4 occurred with SELs ≥186 dB re 1 μPa2s. In F01, significant TTS12-16 (12-16 min post exposure) occurred only at 50 kHz with SELs of ≥177 dB re 1 μPa2s. The highest TTSs (27.5 dB in F02, 29.8 dB in F