Low-to-Mid-Frequency Monopole Source Levels of Underwater Noise from Small Recreational Vessels in the St. Lawrence Estuary Beluga Critical Habitat

Abstract

Anthropogenic noise from navigation is a major contributor to the disturbance of the acoustic soundscape in underwater environments containing noise-sensitive life forms. While previous studies mostly developed protocols for the empirical determination of noise source levels associated with the world’s commercial fleet, this work explores the radiated noise emitted by small recreational vessels that thrive in many coastal waters, such as in the St. Lawrence Estuary beluga population’s summer habitat. Hydrophone-based measurements in the Saguenay River (QC, Canada) were carried out during the summers of 2021 and 2022. Shore-based observations identified 45 isolated transits of small, motorized vessels and were able to track their displacement during their passage near the hydrophone. Received noise levels at the hydrophone typically fell below the hearing audiogram of the endangered St. Lawrence Estuary beluga. Monopole source levels at low frequencies (0.1–≲2 kHz) held on average twice the acoustic power compared to their mid-frequency (≳2–30 kHz) counterparts. The speed over ground of recreational vessel showed a positive correlation with the back-propagated monopole source levels. Estimations of the mid-frequency noise levels based on low-frequency measurements should be used moderately.

Correction: Lagrois et al. Low-to-Mid-Frequency Monopole Source Levels of Underwater Noise from Small Recreational Vessels in the St. Lawrence Estuary Beluga Critical Habitat. Sensors 2023, 23, 1674

“…There was an error in the original publication [1], that phrase is meant to indicate that there is an absence of audiotory stresses.…”

“…There was an error in the original publication [1]. Conclusion #2 states that "the received noise levels [• • • ] mostly fell below the St. Lawrence Estuary beluga hearing audiogram hence suggesting that they caused limited acoustic disturbance at CPA distances of a few hundreds meters".…”

“…Acoustic disturbance in Anse-Saint-Étienne. Each panel (and label) corresponds to a specific event in[1]'s Table1. At CPA, RL levels (in units of dB Hz −1 ) recorded at the hydrophone are shown in light gray.…”