These animals are at risk of collisions with vessels, in a sea of concentrating 25% of the world traffic, the leading cause of non-natural mortality in large cetaceans.
July 10, 2020 21h49
In the Mediterranean, tourism, threat of new cetaceans
LA CIOTAT — schools of dolphins undulating near the coast, groups of sperm whales in areas that are unusual: in the Mediterranean sea, the containment decreed against the coronavirus took the opportunity to cetaceans, but the tourist season could ruin everything.
“As soon as the boaters came back, it was seen that the videos that we have spiky hair,” says Marion Leclerc, of the scientific association for the conservation of cetaceans of the “Souffleurs d’écume”.
One of them shows an “encounter” with a whale in the gulf of Saint-Tropez, on the Côte d’azur: the boat approaches within a few metres and three teenagers throw themselves on the cetacean equipped with simple masks and snorkels. Dangerous for the whale… as for the man: “We are talking about an animal that weighs 70 tons!”, said Ms. Leclerc.
The association “Souffleurs d’écume” is concerned to see come back with some operators who will “stalk” the animals by drone and then offer to tourists to swim with them.
“Many people forget that the Mediterranean is also a home, where animals feed, breed, rest,” said the association, which form of tourism operators to practice responsible observation of marine animals.
Any small sea – 1% of the world surface oceans, the Mediterranean is home to more than 10 000 species. 21 kinds of whales on the 87 listed in the world – have been found in its waters and those of the Black sea, according to the international Union for the conservation of nature (IUCN). Most are classified as “in danger”.
In addition to the encounters with tourists too excited, these animals are at risk of collisions with vessels, in a sea of concentrating 25% of global traffic. “It is the first cause of non-natural mortality in large cetaceans,” according to Marion Leclerc.
Sensors of its
In the bay of La Ciotat, a fifty dolphins in blue and white dip on a summer morning around the inflatable boat of the Scientific Interest Group for Marine Mammals of the Mediterranean (GIS3M).
At the bar, even so, laurène Trudelle says: “it is necessary to reduce its speed, placing themselves parallel to their trajectory in order to avoid cutting the road, after they come to play if they want!”.
During the months of confinement, the almost complete halt of maritime traffic, has allowed some whales to conquer spaces that are usually too much frequented by man. Even the oldest of them, aged one hundred years, had never known such peace.
“Many people forget that the Mediterranean is also a home, where animals feed, breed, rest ”
The association Souffleurs d’écume
With his team of researchers, Hervé Glotin, bioacousticien at the University of Toulon, analyzed data collected by unmanned aerial vehicles marine society Sea Proven, thanks to the sensors of the sounds that helped keep track of cetaceans, and does not affect.
These animals sense and move through their sonar: they detect obstacles in their way by emitting sound waves and then analyzing those returned by the objects.
Decrease of 30 decibels
During the confinement, while all the outputs scientists at sea were shut down in the Mediterranean Sea Proven has obtained the necessary authorizations and funding from the foundation Prince Albert II of Monaco to continue his observations in the “sanctuary” marine Pelagos.
She has recorded a striking decrease of 30 decibels in the coastal areas, the total absence of recreational boaters.
In this “silence”, the cetaceans, including whales, usually quite solitary, have been able to interact “with lengths from two to six times more important than usual,” explains Hervé Glotin, which allowed them to contact fellow very far away.
The dolphins have taken advantage of the absence of the men to go play in the calanques of Cassis, near Marseille. “The period has shown that it is really responsible for the noise in the bays and that this pollution is totally reversible,” says the scientist.
Other pollution have also dropped considerably in the Mediterranean sea: the Quiet-Sea has pointed to a decline to half the levels of hydrocarbons in the water.
The backup of the cetaceans are not the subject of any international treaty binding on the shipowners. Only France requires from 2017 to the French ships of more than 24 metres flowing in Pelagos is equipped with a device for the localization of these animals, complains the NGO for the protection of large cetaceans Tethys, based in Milan.
“When you think that it would be sufficient to reduce to 10% the speed of boats in areas heavily populated by cetaceans to split significantly the sound power level and the risk of collisions!”, lance M. Glotin.