Noisy Waters
Petter Ludvigsen
The oceans aren’t as calm as you’d think. Constant traffic, and general disturbance are all destroying the biggest natural habitat on earth. The blue whale is the largest mammal on our planet. Ranging up to 30m and as heavy as 160 tonnes, the blue whales swim at a speed only slightly faster than a human walking pace at 7 km/h. They stay close to the surface in order to breathe, but when they hunt their prey, krill, they dive around 150 meters deep before they shoot up, open their mouths and devour tonnes. A blue whales migratory pattern is closely related to the krill, staying nearer poles in the summer and moving closer to the equator during the colder months due to the access to krill.The blue whales have calls that can reach over 1600 km away because their calls have a frequency of 10-40 Hz. A human will speak at a frequency of 50-2000 Hz and hear sounds ranging from 20-20000 Hz.These lower communication-frequencies are disturbed by man made noise and could often overlap and drown out their calls.Two of the blue whales biggest acoustic enemies are shipping vessels and seismic surveying. Shipping lanes are unavoidable for marine animals and the ships move. They move faster than the blue whale making them hard to avoid. Their engines and propellers can be as loud as 188 dB, and could disorient and damage the animals more than 3km away. Another noisy enemy of the whale are seismic surveys conducted by ships looking for oil. They shoot air over 200 dB to the ground and read the results with hydrophones.These could cause damage, disorientation and death to marine animals. These surveys combined with the shipping vessel make up a lot of the oceans making them partially inhabitable for many aquatic animals. A whale migrating from outside of Iceland towards the canary islands might cross paths with a shipping vessel at the same time as a survey is conducted, killing their communication.