CHENNAI: Marine experts and environmentalists have renewed calls to urgently address marine noise pollution, warning that rising underwater noise caused by human activities is increasingly disrupting ocean ecosystems and threatening marine life.
Marine noise pollution, also known as underwater noise pollution, is mainly generated by commercial shipping, oil and gas exploration, seismic surveys, offshore construction, and military sonar operations. Unlike on land, sound travels faster and farther in water, allowing noise to spread across vast ocean areas and affect marine organisms over long distances.
The rapid expansion of global shipping has emerged as one of the most significant contributors to underwater noise. Nearly 250,000 vessels operate across the world's oceans, with large cargo ships emitting sound levels reaching up to 190 decibels, comparable to the noise produced by a rocket.
Speaking to DT Next, Dr Chandrasekaran, former Principal Scientist at the Central Institute of Brackishwater Aquaculture, said marine mammals such as whales and dolphins are particularly vulnerable because they rely heavily on sound for communication, navigation, hunting, and locating prey. Increased underwater noise can mask natural sounds, forcing animals to alter their vocalisations, which affects their ability to communicate effectively, he said.
At the global level, the International Maritime Organisation has issued guidelines to reduce underwater noise through improved ship design, maintenance, and operational measures
As countries increasingly focus on the marine economy, especially deep-sea mining, there is a growing need to treat marine noise pollution with the same seriousness as carbon emissions, Dr Chandrasekaran stressed.
Scientists have observed whales and dolphins changing the pitch and volume of their calls in noisy waters, making it difficult for individuals of the same species to recognise one another. Dolphins exposed to persistent noise may become separated from their groups and show reduced reproductive capacity.
The impact of underwater noise extends beyond marine mammals. Fish, squid, sea turtles, and zooplankton are also affected. Prolonged exposure can cause stress and damage the hearing organs.
Seismic surveys using powerful airguns for offshore oil and gas exploration have been linked to internal organ damage in squid and large-scale mortality of zooplankton, disrupting marine food chains.
Experts warn that Indian waters are increasingly exposed to underwater noise due to dense shipping traffic. Studies have found that noise levels along India's East Coast are slightly higher than the West Coast, with an overall increase of nearly 20 decibels, largely attributed to constant vessel movement.
At the global level, the International Maritime Organisation (IMO) has issued guidelines to reduce underwater noise through improved ship design, maintenance, and operational measures.
Experts note that reducing ship speed by just 10 per cent could significantly cut ocean noise, lower emissions, and reduce whale collisions, highlighting how simple measures can deliver major conservation benefits.