Underwater noise characterization of a typical fishing vessel from Atlantic Canada

Fishing is a significant economic sector in Atlantic Canada. Increased fishing vessel density raises ocean ambient noise, adversely affecting the marine ecosystem. This study aimed to evaluate the underwater radiated noise emitted by a typical fishing vessel, identify the noise sources, and determine their respective contributions to the overall noise signature of the vessel. Dipole and monopole source levels are estimated through passive acoustic monitoring during sailing and stationary conditions. This is accomplished by employing a set of hydrophones in conjunction with a numerical propagation loss model and oceanography data. This study also addresses the correlation between structure-borne noise and underwater radiated noise. Over 70% of the noise at frequency bands of 63 and 250 Hz and approximately 40% of the noise above 1 kHz were attributed to the diesel engine, indicating that it significantly contributed to the vessel's noise signature with the propeller. In the unclutched propeller mode, the vessel engine continues to generate noise 40 dB above the background noise and peaks at the 250 Hz band. By addressing this knowledge gap, we can potentially contribute to future endeavours to enhance fishing vessel design and lower the impact of individual noise sources.