Underwater noise emissions by ships pose threat to Indian marine species, says study

The noise results in injuries and changes in their behavioural response besides a shift in their migration route much to their loss

Updated - February 19, 2023 10:26 am IST

Published - February 19, 2023 12:02 am IST - VISAKHAPATNAM

The rising man-made (anthropogenic) underwater noise emissions (UNE) from ships in the Indian waters are posing a threat to the life of marine mammals like Bottlenose Dolphin, Manatees, Pilot Whale, Seal, and Sperm Whale.

The main form of energy for multiple behavioural activities of marine mammals, which include mating, communal interaction, feeding, cluster cohesion and foraging, is based on sound.

However, the sound that radiates from ships on a long-term basis affects them and results in internal injuries, loss of hearing ability, change in behavioural responses, masking, and stress. There are Acute and Chronic noise categories in the emissions.

The UNE or underwater sound pressure levels in the Indian waters are 102-115 decibels, relative to one microPascal (dB re 1µ Pa). The East Coast level is slightly higher than that of the West. There is an increase by a significant value of about 20 dB re 1µPa.

Continuous shipping movement is identified to be a major contributor to the increase in the global ocean noise level, according to a new study titled “Measuring Underwater Noise Levels Radiated by Ships in Indian Waters” at the Visakhapatnam Port (for the East) and Goa’s Mormugao port (for the West) by Andhra University’s marine engineering research scholar G.V.V. Pavan Kumar under the guidance of Prof. V.V.S. Prasad.

“The frequencies of ships’ underwater self-noise and machinery vibration levels are overlapping the marine species’ communication frequencies in the low-frequency range of less than 500 Hz. This is called masking, which could have led to a change in the migration route of the marine species to the shallow regions and also making it difficult for them to go back to the deeper water,” Mr. Pavan Kumar tells The Hindu.

How the underwater ambient noise levels were measured

The measurement of the ambient noise levels was carried out by deploying a hydrophone autonomous system around 30 nautical miles from the Goa coastline. The depth of deployment of the sensor was 11 metres in a water depth of 22 metres. The single-channel hydrophone was deployed at different locations with an in-water depth of 18 metres with a deployment depth of 3 and 5 metres off Visakhapatnam port.

0 / 0
Sign in to unlock member-only benefits!
  • Access 10 free stories every month
  • Save stories to read later
  • Access to comment on every story
  • Sign-up/manage your newsletter subscriptions with a single click
  • Get notified by email for early access to discounts & offers on our products
Sign in


Comments have to be in English, and in full sentences. They cannot be abusive or personal. Please abide by our community guidelines for posting your comments.

We have migrated to a new commenting platform. If you are already a registered user of The Hindu and logged in, you may continue to engage with our articles. If you do not have an account please register and login to post comments. Users can access their older comments by logging into their accounts on Vuukle.