Noise pollution affects dolphins’ ability to communicate

Subject: Environment

Section : Pollution

Context:

A new study has found that noise generated by human activity makes it harder for dolphins to communicate and coordinate with each other. As the levels of underwater noise increase, these mammals have to “shout” at each other.

How does anthropogenic noise interrupt the dolphins’ communication?

Dolphins communicate through squeaks, whistles and clicks.
They also use echolocation in order to locate food and other objects.
Anthropogenic noise coming from large commercial ships, military sonars or offshore drilling can severely impact their well-being.
Impact includes:
- Raising the volume
- increasing the length of their calls
- change the body language

Consequences of increased noise pollution in oceans:

As sound travels faster in water than air, it makes for an important mode of communication because it can convey a lot of information quickly and over long distances.
Fish species rely on sounds during reproductive activities, including mate attraction, courtship and mate choice. Noise pollution can disrupt these activities.

Project Dolphin:

Project Dolphin will involve conservation of Dolphins and the aquatic habitat through use of modern technology especially in enumeration and anti-poaching activities.
The project will engage the fishermen and other river/ ocean dependent population and will strive for improving the livelihood of the local communities.
The conservation of Dolphin will also envisage activities which will also help in the mitigation of pollution in rivers and in the oceans.
It will include oceanic as well as Gangetic river dolphins, which were declared a National Aquatic species in 2010.
Dolphins are one of the oldest creatures in the world along with some species of turtles, crocodiles and sharks.
Ganges river dolphins once lived in the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Nepal, India, and Bangladesh. But the species is extinct from most of its early distribution ranges.
The Ganges river dolphin can only live in freshwater and is essentially blind.
They hunt by emitting ultrasonic sounds, which bounces off of fish and other prey, enabling them to “see” an image in their mind.
IUCN status of Ganges river dolphin:

Gangetic river dolphin

The Gangetic river dolphin is India’s national aquatic animal. It is a Schedule I animal under the Wild Life (Protection) Act, 1972. It has been declared an endangered species by the International Union for Conservation of Nature (IUCN).
The Gangetic river dolphin is one of four freshwater dolphin species in the world. The other three are found in the Yangtze river in China (now extinct), the Indus river in Pakistan and the Amazon river in South America.
The dolphin is found in India, Bangladesh and Nepal. It is blind and finds its way and prey in river waters through echolocation. Bihar is home to around half of the estimated 3,000 Gangetic dolphins in India.
Dolphins prefer water that is at least five to eight feet deep. They are usually found in turbulent waters, where there are enough fish for them to feed on.
Gangetic dolphins live in a zone where there is little or no current, helping them save energy. If they sense danger, they can dive into deep waters. The dolphins swim from the no-current zone to the edges to hunt for fish and return.

Indus Dolphin

Scientific Name: Platanista minor.
Habitat: Indus river dolphins are one of only four river dolphin species and subspecies in the world that spend all of their lives in freshwater.
Distribution: The Indus river dolphin is the second most endangered freshwater river dolphin. At present, there are only around 1,800 of these in the Indus in Pakistan. Their population in the Beas River is between eight to 10.
IUCN status: Endangered.

Characteristics:

Indus Dolphins are brown/grey in colour.
They are functionally blind and rely on echolocation to navigate, communicate and hunt prey including prawns, catfish and carp.
They live for at least for 30 years and grow over 2 metres in length.