“Blue Whisper" immerges into the ocean's fascinating underwater world and gets to the bottom of a widely unexplored field of underwater science: the communication amongst fish.
The documentary accompanies a team of specialists to overwhelmingly beautiful coral reefs, ancient shipwrecks in the Mediterranean Sea, and sunken submarines that are clouded in secrecy, to explore the versatile forms of underwater communication.
What language do fish use? Do they make sounds? Do they have body language? And what role do colors play? With the aid of complex underwater video and audio equipment, those and further questions are answered during a suspenseful journey around the world.
The Red Sea in the south of the Sinai Peninsula, an old wreck lying at the Strait of Bonifacio as well as the depths on the US-American east coast are among the astonishing locations visited and filmed by the team.
In a beautiful coral reef, the team finds an underwater city that - regarding the variety of communication forms - is impressive: the cleaner shrimps that liberate certain fish from parasites use body language to communicate with their customers.
Others like a species of perches make their decision in mate selection on grounds of the female's color pattern and head movements.
Some perches and snappers even manage to convince a moray eel to go on the hunt for them, simply by nodding their heads, a highlight of inter-specific communication and cooperation.
In the course of the film, flashlight fish will be found. During their night-time hunt for plankton, the fish use their glowing eyes, to send a morse code to their fellows. In this way the fish coordinate and orient themselves in the darkness of the night.
As we dive deeper into the ocean, we find an accumulation of about 100 Sand Tiger Sharks assembled in an old ship cemetery. The sharks, all-female and pregnant, hideout from their intrusive males around an old sunken submarine. Sharks have an extraordinary good perception for low sound frequencies between 20 and 100Hz. If exposed to those frequencies, how will the sharks react? Will they become aggressive? How will other species react to that possible aggression? A suspenseful experiment will shed light on this underwater secret.
Lined by interesting experiments ”Blue Whisper” covers a subject that only a few people have documented so far. The young science of underwater bioacoustics has just begun and many new things are to be discovered…