SortAnd our ears were made to hear in the water in many marine areas we would hear a Click chatter, whistles, sounds and verses of various kinds That only one tool, the hydrophone, manages to detect. To emit them They are not fish, but cetaceans, mammals like us. If it is already difficult to communicate with a chimpanzee, which shares 99 percent of the genes with us, It seems impossible to understand the sounds in the water of a dolphin or a megattera.
In Italy there is an all -female team that tries. The manager is Daniela Silvia Pace, The researcher of the University Consortium of the Sea Sciences and coordinator of the group of ecology and acoustics of the marine mammals of the Tor Vergata University of Rome. With her they collaborate with the doctoralities Maria Silvia Labriola at the same University, Alice Turchi at the Sapienza and the research assignist of the University of Bari, Sofia Rinalduzzi. “Abroad, Marina bioacoustics developed mainly after the second world conflict “ explains peace.
«In Italy it took off in the mid -eighties. Requires a work of great precision and attitude to analysis, also with the use of statistical tools and artificial intelligence. It is on the boat for weeks to acquire the data, then months in front of the computer. In my experience, Above all, the girls are attracted.
It is a scientific research work to produce knowledge and provide useful tools for the conservation of these species »points out peace. By studying the cetaceans we come across the pollution problems of our seas and the consequences of climate change. And the reactions of these are discovered Intelligent animali to survive. Because the blue whalewhich weighs up to 160 tons, it is the largest living being on the planet, but we humans are the most dangerous. Not only whales and dolphins.
A sperm whale in the Ligurian Sea while lifting his caudal fin before immersing himself (Daniela Silvia Pace).
“There are about 85 recognized species of cetaceans, in the seas and oceans,” explains Alice Turchi. “Five are fresh water, like the Inia, present in the Amazon Rio”.
The cetaceans are divided the two main groups. THE mystinetsto which the whale and the megatteand which can live up to over 150 years, are equipped with fanoni instead of the teeth, which serve to filter the water by retaining the zooplankton of which they feed on. The dentallike theORCAThe sperm whaleThe turso and the narwhal They are equipped with teeth and remain alive of up to 40-50 years. There are orche that even hunt dolphins, seals and marine lions: No Orca has ever killed a human being at sea.
Sounds at different frequencies
«Through specialized anatomical structures, All cetaceans produce sounds “ explains peace. The sound travels faster in the water compared to the aircan be modulated and is an excellent vehicle of information. «At certain depths, the light does not penetrate. The cetaceans exploit sounds as an instrument of communication and underwater “vision” for Keep social relationships, find prey, orient themselves in the dark. They know how to modulate frequencies.
The whalefor example, to communicate with another specimen they emit sounds to very low frequenciesable to travel to long distances. Dolphins, if they have to look for food, emit Short and high frequency signals called click. It is the same principle that uses the bat: from how the sound against the obstacle bounces, the cetacean understands what distance is the potential prey And even if it is an excitement or a squid ». This is an extraordinary talent.
Daniela Silvia Pace and her work team aboard the research boat (Daniela Silvia Pace).
We humans are capable of storing thousands of visual images. A dolphin, on the other hand, does it with acoustic images. His brain presents a huge surface where you can keep all this information. And if he has to rest, he does it with half a brain at a time: with one part he sleeps, With the other it holds an open eye and moves to return to the surface regularly to breathe.
Dolphins are social animals
Unlike whales, more solitary, Dolphins are very social animals. They live in groups and using nasal aerial bags and phonic lips are able to issue Click to look for foodand whistles to communicate. “They have friendships and whistles serve to establish relationships,” he explains Maria Silvia Labriola, who studies the “Fischi signing” In the tursoone of the species of dolphins best known in our seas. «Each specimen has its own.
When he meets another dolphin of another group, he repeats his whistle repeatedly in sequence. As if he said “Hi, I’m Luca, I’m Luca I’m Luca” “. It seems that each individual develops his whistle signs in the first months of life.
Sofia Rinalduzzi at sea to photograph and identify the specimens sighted (Daniela Silvia Pace).
Sofia Rinalduzzi studies the acoustic emissions of the tursiopi who interact with the fishing. Working on the “Capitolini dolphins” project (aimed at the knowledge of the Tursaope in the waters of the Roman coast and produce useful information for the conservation of the species), found the Presence of sounds called “Bray-Call”, which seem to be the sparse of a donkey. These are various types of low frequency sounds, short -lived and in sequence.
The function is not yet clear And it is not known if they are part of the vocal repertoire of all the populations of Tursaope. But it is certain that There are in two geographical areas of the Mediterranean and that are issued in contexts social and feedsre. «We compared 13 sequences with those produced by Tursiopi SicilianI: only two were in common, and this made us think of a sort of “Local dialect”»Explains Rinalduzzi.
Tursaope in the Roman coast during acoustic and visual reliefs for the “Delfini Capitolini” project (Daniela Silvia Pace).
The sperm whale, Despite being a dedontocete like the dolphin, emits almost exclusively click. “Also in this case it is the arrangements that make the difference,” explains Pace. «It can go down to 3000 meters deep and to locate a prey uses very close clicks. To communicate, however, arrange the clicks forming acoustic patterns called “codas”, typical of the various populations. For example, I can have ClickClick-Click-Pausa-Click (3+1) in the case of a sperm whale Mediterraneanor click-PAUSA-CLICK-PAUSA-CLICK-CLICK-CLICK (1+1+3) for one of theAtlantic”.
The problem of fishing networks
The marine sound landscape is increasingly conditioned by human presence. The oceans are furrowed by huge cargo ships, submarines, boats of every size and type that emit noise. The mining investigation activities on the seabed are another source of noise pollution. All this ends for disorient the cetaceanswhose sounds are covered by human ones. “The whales react by lowering the frequencies, the tursiopi raising them, committing more energy,” explains peace.
The megatte they are known for theirs cups of courtship. In the last decade, in Australia in the reproduction places it has been noted that they sing less. They get closer to females and exhibit their prowess by jumping. A further threat is given by fishing. The excess of fish exploitation deprives the cetaceans of their food. Then, there is the problem of networks. Alice Turchi deals with brands, that is, of all those signs, scars, skin lesions that indicate the state of health of a specimen.
«We have noticed that male tursiopi have more wounds from fishing tools, perhaps because they interact with networks to take advantage of an easy meal. The females, having the puppies, are more cautious ». If it remains stuck in the train networks, The dolphin is sentenced to death: It can no longer go back to breathing. Plastic, also ingested by mistake, also causes death. And in these cases It would be up to us to raise the voice.
Climate change causes Krill’s death, the crustaceans they feed on, pushing them to new behaviors
The climate change damages cetaceans in several ways. “The acidification of the oceans causes Krill’s death, made of small crustaceans, of which the whales feed on” Daniela Silvia Pace explains. «Even if the cetaceans may seem unhappy from the temperature that rises, changes the availability of their prey, forcing them to change the migratory habits to the north ».
The Sedna project is underway, coordinated by the CNR-IAS of Capo Granitola with the La Sapienza University of Rome and the Zoological Station of Naples that investigates climate change in the Arctic territory and tries to grasp the consequences on migratory behavior and food of the whale. «The whale tends to stay at the Almabard, Given the change in terms of temperatures and prey. And instead of singing in the reproduction areas, which are located in the south, It does so by remaining in the arctic waters “ explains peace. The consequences will come.
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