ABSTRACT

Among various factors influencing the ocean noise levels, shipping traffic radiated underwater noise levels were identified as the major contributors. The increase in ambient noise levels due to natural and anthropogenic sources threatens the marine species communication. India has a coastline of 7,516.6 Km with 12 major and ∼187 minor ports. The hydrophone system measured for 39 days helped in investigating the distant shipping traffic lane noise levels and its influence on ambient noise levels of the region. The ocean noise levels measurement were ∼115 dB re 1 µPa for the prevailing environmental conditions. The noise exposure levels were ∼10 dB higher at <1 kHz due to ship passage to and from the port. The fish noise dominated the ambient sea noise mostly at high frequencies >1 kHz. The maximum and minimum range of shipping noise spectra for both the month’s data indicated peak sound pressure level in the lower frequency. Thus, the outcome of the measurements helped in understanding ocean noise levels off the coast of Mormugao Port and the influence of shipping traffic. A similar study for longer duration shall be useful to develop specific traffic lanes in the port entrance which is free from the mammal movements.

摘要

在影响海洋噪声水平的各种因素中，船运辐射的水下噪声水平被确定为主要贡献者。由于自然和人为来源引起的环境噪声水平的上升威胁到海洋物种的交流。印度海岸线长7,516.6公里，有12个主要港口和约187个次要港口。对水听器系统进行了39天的测量，有助于调查远方运输车道的噪声水平及其对该地区环境噪声水平的影响。在主要环境条件下，海洋噪声水平的测量值为〜115 dB re 1 µPa。由于船舶进出港口，在<1 kHz时，噪声暴露水平高出约10 dB。鱼噪声主要是在> 1 kHz的高频下主导周围的海洋噪声。两个月数据的运输噪声频谱的最大和最小范围表示较低频率中的峰值声压级。因此，测量的结果有助于了解莫尔莫高港沿岸的海洋噪声水平和运输交通的影响。进行较长时间的类似研究将有助于在港口入口处建立无哺乳动物运动的专用行车线。