Fisheries and Oceans Canada, 850, Route de la Mer, Mont-Joli, Québec G5H 3Z4, Canada.
J Acoust Soc Am. 2011 Dec;130(6):3661-73. doi: 10.1121/1.3658449.
The threatened resident beluga population of the St. Lawrence Estuary shares the Saguenay-St. Lawrence Marine Park with significant anthropogenic noise sources, including marine commercial traffic and a well-established, vessel-based whale-watching industry. Frequency-dependent (FD) weighting was used to approximate beluga hearing sensitivity to determine how noise exposure varied in time and space at six sites of high beluga summer residency. The relative contribution of each source to acoustic habitat degradation was estimated by measuring noise levels throughout the summer and noise signatures of typical vessel classes with respect to traffic volume and sound propagation characteristics. Rigid-hulled inflatable boats were the dominant noise source with respect to estimated beluga hearing sensitivity in the studied habitats due to their high occurrence and proximity, high correlation with site-specific FD-weighted sound levels, and the dominance of mid-frequencies (0.3-23 kHz) in their noise signatures. Median C-weighted sound pressure level (SPL(RMS)) had a range of 19 dB re 1 μPa between the noisiest and quietest sites. Broadband SPL(RMS) exceeded 120 dB re 1 μPa 8-32% of the time depending on the site. Impacts of these noise levels on St. Lawrence beluga will depend on exposure recurrence and individual responsiveness.
圣劳伦斯河河口受到威胁的居留白鲸种群与重大人为噪声源共享萨格奈-圣劳伦斯海洋公园，包括海洋商业交通和成熟的、基于船只的观鲸产业。频域（FD）加权用于近似白鲸的听觉敏感性，以确定在六个高白鲸夏季居留地的六个地点，噪声暴露随时间和空间的变化情况。通过在整个夏季测量噪声水平，并根据交通量和声音传播特性测量典型船只类别的噪声特征，估计了每个声源对声栖息地退化的相对贡献。刚性充气艇是研究栖息地中相对于估计的白鲸听力敏感性的主要噪声源，因为它们的出现频率高、接近度高，与特定地点的 FD 加权声级高度相关，并且在其噪声特征中以中频（0.3-23 kHz）为主。根据不同的地点，噪声加权声压级（SPL（RMS））的中值范围在最嘈杂和最安静的地点之间为 19 分贝。宽带 SPL（RMS）取决于地点，有 8-32%的时间超过 120 分贝。这些噪声水平对白鲸的影响将取决于暴露的复发和个体的反应能力。
