Can noise from ships harm dolphin and whale communication?

In one line

The rule

Dolphins and whales use sound waves to communicate, find food, and navigate. Loud human-made noises in the ocean can interfere with these sounds, making it hard for them to hear each other.

Let's understand it simply

Imagine you are in a crowded market during Diwali. People are shouting, crackers are bursting, and loudspeakers are playing music. If your friend is standing just 10 meters away and calls your name, you may not hear them. This is because all the other sounds are drowning out your friend's voice.

Dolphins and whales live in the ocean, which is usually a quiet place. They "talk" to each other using special sounds, like whistles and clicks. Ships, however, make loud noises underwater, like a pressure cooker whistling non-stop. These noises can cover up the sounds dolphins and whales make, just like the market noise covers your friend's voice.

How it works

1. Dolphins and whales make sounds to communicate, find food, and navigate (move around).
2. These sounds travel as waves through water, which carries sound very well.
3. Ships, especially big ones, make loud, low-pitched noises with their engines and propellers.
4. These noises spread far in the water, sometimes for many kilometers.
5. The ship noise overlaps (covers up) the sounds made by dolphins and whales.
6. As a result, dolphins and whales cannot hear each other clearly, get confused, or even get lost.

The story behind it

Scientists started noticing in the late 20th century that whales and dolphins were behaving strangely near busy shipping lanes. Some whales even got stranded on beaches. Researchers then used underwater microphones (hydrophones) to listen to the ocean and found that ship noise was much louder than natural ocean sounds. This led to many studies on how human noise affects sea animals.

One famous case was in the 1980s, when scientists recorded blue whales changing their songs in noisy areas. This showed that whales were trying to "shout" over the noise, just like you might raise your voice in a noisy classroom.

Where you see it in real life

• Cargo ships in the Indian Ocean: Their engines make a constant rumbling sound underwater, disturbing whale communication.
• Ferry boats near Mumbai: Dolphins near the coast may swim away or stop making sounds when boats pass by.
• Oil drilling platforms: The machines used for drilling make loud, continuous noises, affecting whales and dolphins nearby.
• Navy sonar exercises: Powerful sonar can confuse or even injure whales, causing them to strand on beaches.
• Fishing trawlers: Their motors and winches add to the underwater noise, making it hard for dolphins to find each other.
• Tourist boats in Goa: The noise from many boats at once can make dolphins leave the area.

Why it matters

• Navigation: Dolphins and whales use sound to "see" underwater (echolocation). Noise can make them lose their way or bump into things.
• Finding food: If they can't hear echoes, they may not find fish or squid to eat.
• Social life: Dolphins and whales live in groups. If they can't talk, they can't warn each other about danger or stay together.
• Health: Long-term noise can stress these animals, making them sick or affecting how they raise their young.

Common mistakes

• Thinking only loud noises matter: Even constant, low-level noise can disturb whales and dolphins.
• Believing animals will "get used to it": Many studies show that these animals do not adapt; instead, they may leave their home areas.
• Assuming all sea animals are affected the same way: Dolphins and whales are more affected because they rely heavily on sound, unlike fish that use other senses too.
• Forgetting that noise travels farther underwater: Sound moves faster and farther in water than in air, so ship noise can affect animals many kilometers away.

Remember it

Dolphins and whales "talk" with sound. Ship noise is like shouting in their classroom, making it hard for them to hear each other.