Ship noises to double every 10 years, hit marine life: Study
MUMBAI: Ship movement in the Arabian Sea, the Bay of Bengal and Indian Ocean causes noise levels to double every 10 years, affecting marine life, according to a study by the Maritime Research Centre (MRC), Pune, under the Indian Maritime Foundation that was released a day before the World Oceans Day (June 8).
The study, Acoustic Habitat Degradation Due to Shipping in the Indian Ocean Region (IOR), states decibel (db) levels in the seas have increased from a maximum of 185-190db to 210db over seven decades.
In this period, the minimum noise levels along major shipping routes, too, have gone up to 110db from 90-95db.
The increasing noise could have an adverse impact on marine life, adding that the rise in cases of whales and other marine mammals dying along the coast could be attributed to shipping.
According to the United Nations Conference on Trade and Development (UNCTAD), the Indian Ocean, Arabian Sea and Bay of Bengal represent 20% of the world’s oceanic area.
Apart from Navy ships and vessels deployed for security pur- poses, seaborne trade, including regular export-import goods, dry cargo, petroleum products, gas load, and crude oil, has increased from 5,000 million tonnes (mt) in 1970 to 20,000 mt in 2014 (UNCTAD).
More recent data from the Indian National Shipowners’ Association shows the trade increased to 27,500 mt by 2017.
Noise from ships causes discomfort to marine mammals, in some cases leading to internal injuries, bleeding and haemorrhages, or even death, said researchers. “Movement of ships propagates noise below 1 khz. Marine mammals have different frequency bands for multiple functions such as navigation, communication, foraging, finding mates for breeding, and avoiding predators. For instance, the Blue whale uses 300Hz to communicate, while dolphins and porpoises use around 150 khz. When the sound of the ships matches the frequency of their communication signals, it affects them internally,” said Arnab Das, author of the study and director of the Maritime Research Centre.
“The situation can get better only if the union environment ministry intervenes,” said E Vivekanandan, consultant and scientist, Central Marine Fisheries Research Institute, Chennai.