Noise makes it hard for the dolphins to communicate and use echolocation to navigate in shallow water, increasing the risk of getting stranded
Shipping noise can interfere with the critical activities of the Ganges dolphin, decreasing survival rates and population. Illustration (created with the help of DALLE 2): Gargi Roy Chowdhury. Sound is a sensation. It is either music to our ears or distress on our drums. I have found the sound of a river to be soothing. Due to my job, I often spend the night on a boat. The flowing river reduces stress and anxiety when I am in the field. I find it easier to relax and meditate when near a flowing river. Listening to natural sounds helps me fall asleep faster and sleep more soundly.
After waking up in the morning, I am greeted by the sweet melody of the birds as they pass and the quiet hum of the wind that gently roars. The sound of water is so serene it feels like a soothing dream. I find the symphony of nature a magical and comforting psalm.
Also read: Thriving Gangetic dolphin presence in Bihar, reveals census
The sound of a river can also positively affect our mental health. It can help us feel more connected to nature and the world. This connection can help us feel more grounded and centred, reducing anxiety and depression.
It can also help us feel more creative and inspired, increasing our well-being. To all the readers, I highly recommend that the next time you’re feeling overwhelmed or need to relax, take some time to listen to the sound of a river and let it wash over you.
What was once a magical hymn has now been transformed into a jarring and raucous sound. Instead of the soothing melody I was accustomed to, I was jolted awake in the Hooghly river by the harsh noise of a boat engine and a blaring horn.
While the sound of a river is typically calming and soothing, it can be disrupted by external factors, such as shipping noise. Shipping noise is caused by vessels, boats and ships travelling on the river. It can significantly impact the river’s acoustic environment.
The increase in shipping noise can be attributed to growing global trade and economic activities. As international business has grown over the past few decades, so has the demand for maritime transportation. Ships are becoming larger and faster, which can generate more noise.
The economic benefits of shipping are vast and the global shipping industry is crucial to the functioning of the global economy. World Bank also considers it a greener transport mode than road transportation.
However, shipping noise can be disruptive to both humans and wildlife. For humans, the noise can be a source of annoyance and can lead to increased stress levels. It can also interfere with outdoor activities such as fishing and bird watching, often enjoyed near rivers.
Wildlife is also impacted by shipping noise. Ganges dolphin, the species I work on, rely on sound for communication, navigation, and hunting. Shipping noise can interfere with these critical activities, decreasing survival rates and population.
Illustration (created with the help of DALLE 2): Gargi Roy Chowdhury
A recent study by Dey et al. from National Centre for Biological Sciences found that their metabolic stress levels increase when the dolphins are exposed to vessel noise and shallow water.
The noise makes it hard for the dolphins to communicate and use echolocation to navigate in shallow water, where they risk getting stranded. The increased metabolic stress can lead to long-term health effects and reduced reproductive success.
In addition, terrestrial animals, such as birds and mammals, can be disturbed by shipping noise, leading to increased stress levels and changes in behaviour.
Also read: Ganga's minimum flow notification too vague to be implemented: Scientists
When a noisy tourist vessel approaches, you will surely notice resting birds flushing away from sandbars. A study by Burger et al. found seabirds show strong aversive responses toward ship traffic. Partial resettlement was observed within seven hours after the disturbance by ships. The disturbance effect was more substantial when high-speed vessels passed.
The impact of shipping noise on rivers is not just limited to the acoustic environment. Vessels travelling on rivers can also cause physical disturbances, such as wakes and turbulence. These disturbances can cause erosion along the riverbank, leading to changes in the river’s course and impacting the surrounding ecosystem. Local fisherfolk are wary of using their traditional boats as they risk drowning.
It is essential to take measures to mitigate the impact of shipping noise on rivers to preserve the ecosystem’s health and maintain the benefits of the river’s natural soundscapes.
A few successful initiatives and regulations, such as ‘quiet ship’ standards, have been implemented to mitigate shipping noise. Some countries have implemented laws that require ships to meet specific noise standards.
For example, in the United States, the National Park Service requires commercial tour boats to meet ‘quiet ship’ standards, which limit noise levels to 70 decibels at a distance of 150 feet. This has helped reduce the impact of shipping noise on sensitive areas.
Another one is speed restrictions. Speed restrictions have been implemented in some areas to reduce the noise and disturbance caused by vessel wakes. The National Oceanic and Atmospheric Administration has implemented voluntary speed restrictions for ships in certain areas to protect critically endangered North Atlantic right whales.
Altering shipping lanes can help minimise the impact of shipping noise on sensitive areas. For example, in the United Kingdom, shipping lanes have been moved away from crucial mammal habitats to reduce the impact of shipping noise.
Some companies have developed technology to reduce underwater noise from ships. For example, Evologics, a German company, has developed an underwater noise-reducing system that uses microbubbles to reduce noise levels.
Some ports and shipping companies have implemented voluntary measures to reduce shipping noise. For example, the Port of Vancouver in Canada has implemented a voluntary incentive program for shipping companies that use quieter ships. This program offers financial incentives to companies that use quieter ships, which has increased the use of these vessels.
Also read: COVID-19 lockdown a blessing for the endangered Gangetic dolphin in Bihar: Experts
However, more must be done to protect sensitive areas and wildlife habitats from the impact of shipping noise.
In conclusion, the rapid expansion of the global shipping industry has led to an alarming increase in shipping noise, causing significant disturbances in the natural soundscapes of rivers.
The impacts of this noise pollution are far-reaching and affect both humans and wildlife. The noise generated by shipping activities can cause annoyance and discomfort to humans and interfere with the critical activities of wildlife, leading to alterations in their behaviour patterns.
It is, therefore, imperative to take concrete steps to address the issue and reduce the impact of shipping noise on river ecosystems. This can be achieved by implementing measures such as adopting ‘quiet ship’ standards, imposing speed restrictions and re-routing shipping lanes.
Preserving the natural soundscapes of rivers is essential to maintain the benefits of the river’s ambient sound and safeguard the delicate balance of the surrounding ecosystem.
Gargi is currently working on her PhD at the Wildlife Institute of India, focusing on studying Ganges dolphins in the River Hoogly.
Views expressed are the author’s own and don’t necessarily reflect those of Down To Earth
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