Auditory evoked potential thresholds and pressure-based modeling of potential boat-noise audibility in three cultured sciaenids.

Abstract

Aquaculture constitutes an important food source and the farming facilities are typically located in offshore waters where they are susceptible to disruption from boat traffic, yet the audibility of vessel noise for cultured fishes is rarely quantified. We measured auditory evoked potential (AEP) thresholds expressed as sound pressure levels in three cultured sciaenids from southeast China (yellow drum Nibea albiflora, red drum Sciaenops ocellatus, and blackspotted croaker Protonibea diacanthus). We integrated these thresholds with in situ recordings of passing-boat noise and KRAKEN sound-pressure propagation modeling to estimate potential audibility ranges. All species showed sensitivity between 100 and 2000 Hz, with minimum detection thresholds at 300 Hz. These thresholds were 92.80, 105.69, and 103.43 dB re 1 μPa for N. albiflora, S. ocellatus and P. diacanthus, respectively. Passing boats generated continuous broadband acoustic signatures dominated by engine noise, with a mean peak frequency of 289.72 ± 131.68 Hz, a - 3 dB bandwidth of 58.72 ± 25.90 Hz, and an SPL_rms of 133.44 ± 1.99 dB re 1 μPa, overlapping the frequency band of lowest measured AEP thresholds. Propagation modeling yielded maximum audibility ranges of approximately 93 m (N. albiflora), 23 m (S. ocellatus), and 25 m (P. diacanthus) for a 1.00 m source depth. These estimates are pressure-based and do not account for particle-motion detection or field ambient masking. This work provides the first baseline sound pressure threshold curves for N. albiflora and P. diacanthus and a physiology-informed framework for mapping vessel-noise exposure zones in mariculture to inform noise management strategies.