MEDITERRANEAN SHARKS: FINISH IN VIEW!

More than 40 species of sharks, from the little fruit bat to the great white shark, live in the Mediterranean! We asked Nicolas Ziani, at the head of the AILERONS association, to take stock for us on animals that are poorly known, but nevertheless very present.

RARE DIVING MEETINGS

“It is difficult, admits Nicolas Ziani, to cross the path of a shark in our French Mediterranean waters while diving. It is still possible to meet small fruit bats ambushed in coastal reefs, much more rarely the large fruit bat. It is also possible to meet blue sharks, cases have been reported by divers in Corsica or near Marseille. A few rare "unforeseen" sightings of great white sharks have been recorded in the Marseille region and the most recent would have taken place off Villefranche / Mer in 2002, an animal probably 4 m long. We were also told of a rare case of observation of a common thresher shark of at least 4 meters by an underwater hunter on the site of the Château d'If in Marseille in August 2009. "

THE GREAT WHITES OF THE MEDITERRANEAN

“The great white shark, specifies Nicolas Ziani, Carcharodon carcharias, is very present in the Big Blue, the first description of the species was moreover made in 1758 by the naturalist Carl von Linné in the Mediterranean! And my Italian colleague Alessandro De Maddalena recently published a book ("The great white shark on the French coasts. Editions Turtle Prod") in which he reports more than 600 observations over the whole of the Mediterranean since the Middle Ages, including 44 specimens in French waters! It is not therefore a question of lost individuals. “Fifty years ago, there was a population of great white sharks resident in the Adriatic but which was decimated by fishing. The great white sharks present in the Mediterranean have a coppery brown dorsal livery unlike other world populations. There is a nursery for the species located between Sicily, Sardinia and Tunisia, place where females give birth to their young and where young sharks develop into adulthood. Full females with full term embryos have been captured several times in this area. "

BIG PREDATORS IN DANGER

The sharks are therefore there, but it is extremely difficult to obtain precise data on the state of the populations. A recent IUCN study sounded the alarm on around 15 Mediterranean species, and put sharks and rays in the front line: among the 14 most threatened species (critically endangered), 13 are sharks and rays. Likewise, among the 9 species considered “endangered”, 15 are sharks and rays. And among the 8 species listed as "vulnerable", 7 are sharks and XNUMX belong to the bony fish family. Sharks have a biological cycle that makes them particularly vulnerable to the effects of an external threat such as overfishing. They have late sexual maturity, a limited number of young per litter, an advanced age at first procreation, long reproductive cycles, and a long lifespan. The survival of these species depends on large adult individuals living long enough to be able to reproduce several times and renew the population.

Passion for sharks

Passionate about sharks since his childhood, Nicolas Ziani, marine biologist, trained at the University of Sciences Montpellier II, at the Muséum National d'Histoire Naturelle de Paris and the Mediterranean Coastal Environment Station of Sète, has always multiplied study projects at sea of ​​sharks from French Mediterranean waters for their conservation. He finally created the AILERONS association in May 2006 to develop with other volunteers research and awareness-raising activities for the general public for the conservation of sharks and rays worldwide.

THE GRAND LARGE PROJECT

"We are working mainly on the blue shark (Prionace glauca), explains Nicolas Ziani," but also on the common thresher shark (Alopias vulpinus), two large pelagic and migratory species in our French Mediterranean waters. Since the summer of 2010, in partnership with the recreational fishermen of the National Federation of Pleasure and Sports Fishermen of France (FNPPSF), we have marked 8 blue sharks from 70 cm (newborns) to 150 cm (marking of identification using Tags) off Languedoc-Roussillon, we have already sampled some live blue sharks to study Mediterranean populations of this species, a project in partnership with the CNRS unit of CRIOBE in Perpignan. "

DNA AND TAGS

“We are waiting for this new 2012 season,” he continues, “to develop our sampling work in order to collect a larger number of DNA samples which will then be analyzed by CRIOBE. »This summer must also begin operations to install satellite beacons on blue sharks in Languedoc waters, a great first in French Mediterranean waters, a project partly funded by the Youth Space of the City of Montpellier and also carried out in partnership with CRIOBE which financed the first beacons. These beacons give the animal's location in real time, and should make it possible to better understand the migrations of the species within the Mediterranean and in a more global oceanic context. Operation Shark-Trace 2012 is scheduled for July 28 and 29, 2012 with fishermen from the Cercle des Pêcheurs Cap Agathois (FNPPSF) and the collaboration of ADENA.

LIMIT DEPTH

If you have the chance to observe sharks, it will probably be on the surface. But beware, the fin does not make the shark! It can be a sunfish, a swordfish, even a dolphin or another cetacean for the untrained eyes. And if it is a shark, it is difficult to recognize the species. "" For example, explains Nicolas, the basking shark and the great white shark both have very characteristic very large and triangular dorsal fins, one can often confuse them all the more so that the silhouette of the body slender and massive or their manner of swimming for a long time on the surface can be confusing. "

SEND YOUR OBSERVATIONS!

But if you have seen something, do not hesitate to send your data to the association (contact@ailerons.eu), trying to be as precise as possible given your knowledge. All the information counts: morphological characteristics, sex, size, behavior, geographic location, date, time, duration and conditions of the observation, number of individuals. Ditto for rays: in 2007 the association launched a reporting campaign for a species of ray, the Mediterranean devil Mobula mobular, and 40 individuals have already been reported.

Next year, Nicolas Ziani would like to lead a diving campaign, which would allow him to start photographing Mediterranean sharks.

Text: Isabelle Croizeau