Shipping noise and whales: World tallest ocean liner vs largest animal on earth

摘要

The noise spectra radiated by the world tallest ocean liner, the Queen Mary IE (QM2), when she sailed over the blue whale feeding ground of the Saguenay-St. Lawrence Marine Park in Sept and Oct. 2004 are presented. Recordings for her 4 transits were made from an array of AURAL autonomous hydrophones moored at mid water depth along the navigation corridor at the head of the Laurentian channel. Typical ship noise Lloyd's mirror patterns on spectrogram generally allowed identification of the closest points of approach (CPA) to the hydrophones. The analysis of the Doppler shift of stable QM2 spectral rays allowed estimating CPA ranges and sailing speed. QM2 noise signature is characterized by several strong rays between ～100 to 500 Hz, likely from her propulsion pods. Her average noise spectra are however enclosed within the envelope of the merchant ship noise measured in the area, except for high peaks below 40 Hz and the above rays. Broadband (10-1000 Hz) rms levels varied from 121 to 136 dB re 1μPa. As for most other merchant ships, this radiated shipping noise makes a barrier masking the low-frequency vocalizations of calling blue and fin whales over a large part of the basin.