Where do whales and dolphins come from

Underwater noise

Main source of noise: the military

"Suppose you do not make a fireworks display on the cruise ship, but under water, as an event, just like that. That would be devastating for the whales!", Says Dr. Karsten Brensing, the behavior researcher of the international whale and dolphin protection organization WDC.

One of the main sources of noise are the military with their sonar devices for locating submarines. These sound devices emit a high-pitched beep at short intervals. If the sound is reflected, there is an object (usually another submarine) nearby.

"This noise is unbearable and painful for whales. In terms of us humans, the source of the noise would be so loud as if an explosion in Moscow made it impossible for us here in Germany to have a simple conversation on the street."

Whales listen at a distance from Hamburg to Naples

Water is an excellent transmission medium for sound. The hearing of whales and dolphins is fantastic. They need that too, because the oceans are big.

A reproductive partner is as difficult to find here as the proverbial needle in a haystack. Some species can communicate over a distance of up to 2000 kilometers - this corresponds to the distance from Hamburg to Naples.

But the noise in our oceans has increased so much over the past few decades that the whales can only communicate within a tenth of the area, i.e. up to 200 kilometers - just one of many reasons why populations are not recovering and some species are not recovering are critically endangered.

Huge ship's propellers, engine noise, but also construction work for wind turbines and oil rigs and the search for oil and natural gas are to blame.

Whales can't just listen - just as we humans can't. All you can do is swim away. Mothers and their calves are particularly at risk. They don't get away fast enough and their hearing is damaged.

Noise restricts whale communication

Whales can hear in a radius of 360 degrees. But especially the calls of our native porpoises are directed forward and can only be heard there. Their communication with one another is overlaid and restricted by the noise under water.

Conditions for breeding and conservation are not good. "This problem has been known for years, and something can be done about it - but that only happens when politics demands it from the industry," says behavioral researcher Brensing.

"Instead of ramming the piles for wind turbines into the sea floor with huge blows of a hammer - so-called 'piledriving' - you can mill the pillars into it like a giant screw."

But many large companies refer to the contracts they signed years ago when noise protection was not yet an issue - and their love of animals does not go as far as voluntarily exposing themselves to increased construction costs. Alternatively, heavy concrete blocks the size of containers can be lowered onto the leveled seabed.

"But even as tourists we can help the whales with our leisure activities," says Karsten Brensing. Jet-skiing in particular is noisy - just like many motor yachts - and is usually also offered in areas where whales occur: in the Caribbean, but also here in the North Sea and Baltic Sea.