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

Source: The post is based on the article “Underwater noise emissions by ships pose threat to Indian marine species, says study” published in The Hindu on 21st February 2023

What is the News?

A study has been published titled “Measuring Underwater Noise Levels Radiated by Ships in Indian Waters”.

What are the key findings of the study?

According to the study, 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 Whales, Seals and Sperm Whales.

The UNE or underwater sound pressure levels in the Indian waters are 102-115 decibels (dB). The East Coast level is slightly higher than that of the West. There is an increase by a significant value of about 20 dB.

What is the impact of underwater noise emissions(UNE) from ships on marine ecosystems?

Impact on mating and other activities: Marine mammals like Bottlenose Dolphins, Manatees, Pilot Whale, Seal and Sperm whales use sound for mating, communal interaction, feeding, cluster cohesion and foraging

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 and stress. 

Impact on migration route: The frequencies of ships’ underwater self-noise and machinery vibration levels are overlapping the marine species’ communication frequencies.

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 made it difficult for them to go back to the deeper water.