A recent global report released on World Oceans Day on June 8 highlights the alarming impact of noise pollution on marine wildlife due to the increasing number of marine vehicles and underwater surveys. The report, by the Convention on the Conservation of Migratory Species of Wild Animals (CMS), provides practical guidance on reducing noise pollution from shipping, seismic airgun surveys, and pile driving.
The report emphasizes that anthropogenic noise can cause direct injuries and auditory threshold shifts in marine animals, impairing their communication, ability to detect threats, and find food, sometimes resulting in death. It also states that marine wildlife, including migratory species and their prey, rely on sound for essential life functions such as communication, prey and predator detection, and orientation.
Amy Fraenkel, Executive Secretary of CMS, highlighted the importance of reducing noise to safeguard marine species and commended the report for providing essential guidance in this regard.
The report recommends the application of quieting technologies to reduce sound at the source as the most effective way to mitigate the negative impacts of underwater noise. These technologies not only benefit marine wildlife but also have potential additional advantages, such as reducing greenhouse gas emissions and contributing to climate change mitigation.
For the shipping industry, the report suggests altering ship design, propeller technology, and improving operating conditions as part of Best Available Technology (BAT) and Best Environmental Practice (BEP). Measures like reducing the speed of container and cargo ships, known as slow steaming, can significantly lower the acoustic footprint, fuel consumption, and CO2 emissions. Quieting the loudest 10-15% of ships is particularly important as they contribute disproportionately to overall shipping noise.
Regarding seismic airgun surveys, the report emphasizes the need for quieter alternatives like Marine Vibroseis, which produces controlled, lower-frequency seismic signals, reducing the threats posed to marine life. Mitigation measures are also outlined for situations where these alternatives cannot be employed.
For pile driving, the report highlights the availability of numerous quieting technologies and noise abatement systems, which have been developed in recent years to comply with noise limits set by regulators. However, the report acknowledges that despite the application of best available quieting technologies, further mitigation measures are often necessary to minimize the impact on marine life.
Dr. Lindy Weilgart, the author of the report and an ocean noise expert at OceanCare and Dalhousie University, cautions that certain activities may still have an impact on marine life, even with the application of best available technologies, necessitating additional mitigation measures.