Well-know as sedentary and territorial, he likes littoral rock depths with shelters such as caves or rifts where he finds refuge. He eats molluscs cephalopods, shellfish and fish. The sexual development of the grouper is a successive hermaphrodite of proterogyne type. The sexual inversion would be done on the Tunisian coasts, when 9 years old. Sexual maturity - about 5 years - is late. The growth rate of the brown grouper is weak, but thanks to its great longevity (50 years) he can reach a size of 1,20 m for a weight of 80 lb. The period of laying takes place in July-August in the south of the 41°5 of northern latitude. Very common in the years 1950, the brown grouper, appreciated for its flesh and its value of spearfishing trophy, saw its numbers breaking down.

Their lack of suspicion of men made easy preys. Moreover, it did not seem (or more) to reproduce there: one met only individuals of average and big size, come from the South of the Mediterranean basin. However, at the end of 1980, low-weight juveniles were observed on our coasts, which seems to show that the area of reproduction of the species had extended towards north. This phenomenon still continues and a return of the grouper and the presence of young subjects was observed in the marine areas protected or not. The light reheating of the Mediterranean is not enough to only explain himself this phenomenon.
The effectiveness of the protection from which he profits in protection zones and, since 1993, on the whole of the littoral, unquestionably contributes to the return of the brown grouper in coastal water. Today, the populations of groupers returned on a level which one could describe as reasonable thanks to the decrees of April 2, 1993, November 25, 1997 and December 30, 2002. This last moratorium prolongs until December 31, 2007 the prohibition of brown grouper spearfishing and extends it to all forms of fishing with hook on the whole of the coast of the continental Mediterranean.

The big mother-of-pearl
Pinna nobilis (Linné, 1758)

She lives half inserted in the sediment, rooted thanks to its  filamentous secretion called byssus, mainly in the herbaria with Posidonia oceanica, between the surface and 40 yards deep. Its shell, whose former edge is round, have a triangular form, frayed towards the foot and covered with outgrowths limestones on all its surface. With time, she overlaps almost entirely with a crowd of organizations getting a perfect camouflage, such as algae, sponges, worms, ascidiums, bryozoarias, oysters... The shell is inserted by the point on about a length third, varying according to the size of the subject and the conditions of the sea environment. Nevertheless she can get about slow and limited displacements thanks to its foot, which explains why this shell is found in various levels of depth: the young ones will be located rather in low depth whereas the old subjects meet until less 40 yards. Contrary to the mussels which live in group, mother-of-pearl is solitary and thus it is rare to meet grouped subjects. 

Pinna nobilis has even a host inside his shell: a small crab called pinnotheria. We can often see mother-of-pearl with half-opened valves, because she is filtering water necessary to its oxygenation and its nutrition. Its food is composed by suspended particles and unicellular algae of small diameter. She represents a fundamental interest for the Mediterranean because its capacity of filtration is about 2000 liters of water per day.
The reproduction of Pinna nobilis is difficult. Indeed, it is an hermaphrodite protandre, i.e. that the young individuals are male then transform into females when growing old. It is necessary thus that young and old mother-of-pearl are together when the reproduction can take place. The maturation of eggs and the larval development are done in the open sea. After its planktonique life, the larva, weighed down its shell, falls on the depths and is fixed; she's approximately 2 cm tall. Its shell, transparent, decorated with fine outgrowths limestones, is fragile. Many are its predators: octopuses, seabreams, carnivorous gastropods of the Natica genus. The death rate at this stage is very high. Before abundant in all Mediterranean, she now became rare on our coasts. In the old days, the Romans used his mother-of-pearl to make jewels and the filaments of the byssus to make clothes. The legend says that this fine hair was used to make the famous "Golden Fleece" coveted by the Argonauts.
Today, weakened by the recession of the seaweed, decimated by pollution involving the extermination of the larvae, also decimated by the abusive catching used by divers avid of memories, the anchorage and the trawling done in low depth which destroy their ecosystem, Pinna nobilis and her cousin Pinna pernula owes their safety and the protection of their species thanks to the decree of November 26, 1992.

The float lobster
Scyllarides latus (Latreille, 1803)

Less known than the common sea Cicada "Scyllarus arctus", the big sea Cicada can reach 45 cm length and presents a similar way of life. She live in all Mediterranean, especially in the South and East to the Adriatic. Its activity is night and the day, she is hidden, sheltered from light in the caves or cavities of the rock depths with which it merges thanks to its homochromy. She is red brown, almost black green olive colouring. 

The body is covered by a chitinous carapace impregnated with limestone. It consists of two definitely distinct parts: the cephalo- thorax and the abdomen. With a gregarious behaviour, the sea Cicada is a carnivorous macrophage for which the chewing is external: the preys, mainly of the worms and molluscs, are teared to shreds before being ingested. The float lobster goes on the seabed. When she is threatened, she swims back, trashing the water to the bottom with her swimming pallet located at the end of the abdomen.

Breathing is branchial. The sexes are separate and fecundation is external: the eggs, fixed on the abdominal appendices, are incubated by the female and give birth to flat and transparent larvaes called phyllosomes.
Their flesh is very estimated and their tail (abdomen) is broader and more meaty that Lobsters. Appreciated in the bouillabaisse, the fame of the big sea Cicada is such as she was the object of abusive fishings, often illegal (aqualung). Its aptitude for the reproduction did not compensate its overexploitation, which make of this shellfish a rare species. Indeed, it seems to have disappeared from the Gulf of Lion, but one still locally finds it in Provence-Alp-Coast of Azure and Corsica. The Float Lobster was classified as a species protected in France by the decree of November 26, 1992.

The ferreous limpet
Patella ferruginea (Gmelin, 1791)

The ferreous limpets, still called Chinese Hats, are appreciated for their flesh. They live above the sea level, in a zone beaten by the waves. To survive, they must adhere to the substrate by adapting perfectly the edge of its shell to the asperities of the rock. They move, and eat by grating the algae on its route.

When the patella is collected, one destroys at the same time the number of young subjects because they live fixed on the shell of the adults. Decimated by the fishermen and the pollution, she disappeared from the French coasts since around fifty of years and remains today only in Corsica, Sardinia and Algeria. The marine park of Port Cros reintroduced the ferruginous patella in the zone protected to try save her. It's probably the marine species  the most threatened of fast disappearance in the Mediterranean, in spite of its fishing prohibition in France with the decree of November 26, 1992.

The sea urchin diadem
Centrostephanus longispinus (Philippi, 1845)

The test is brown purplished,rather dark, even black. Like all Diadematidae, he prefers hot water and  thus he is more common in the Eastern part of the Mediterranean. One meets him from Marseilles towards Italy, in Sicily, in Corsica, in the Adriatic Sea, in the Marmara Sea, in Tunisia, in Algeria and out of the Mediterranean, in Azores and Canaries islands. He is also abundant on the small depths of the Eastern Atlantic such as those of Mauritania. He likes rock depths of 15 or 20 m, but he is able to escape in the herbaria of posidonias, or to settle on the muddy depths, well far from surface, around 200 meters deep. The reproduction, the nutrition and the biology of this sea urchin are still imperfectly known.

One knows that during his life, the sea urchin diadem passes by a planktonique larval phase, in the open sea, little known nowadays! The very young sea urchins, resulting from its larvae, were never seen... and one really does not know what they look like.
"The smaller" known sea urchins diadem had already 1 cm diameter, except prickles, and were as rare as their parents. Between 2 and 5 centimetre diameter, the sea urchin grows from approximately 1 millimetre per month. These young sea urchins could be brought episodically along the French coasts by the marine currents coming from the south of Italy, then carryed later by the liguro-provençal current.
According to the biotope where the sea urchin moves, one finds in his stomachic contents remains of animals (spicules of sponges, remainders of shells...) or a strong proportion of plants (algae or seasweed). A part of the dissolved organic matter in water is also absorbed in particulate form. The great prickles carry for this purpose long longitudinal furrows, very visible with the microscope. It is supposed that the great mobility of the prickles ensures an effective mixing of water, and a good absorption of the particles. Rare, the sea urchin diadem was classified as species protected in France by the decree of November 26, 1992. Sensitive to pollution, attracting for the eye of the divers and very exposed to the nets or dredgers, its collecting is prohibited and the rare collected specimens must be given to sea. 

The european date mussel
Lithophaga lithophaga (Linné, 1758)

The shell of the date mussel relatively large, is lengthened, in the date shape, from where its name. The two ends are round, and the surface present small concentric strias and thick transverse ribs. The shell is white, but the periostracum, external organic layer covering the shell, is brown colouring. Possible confusion with Myoforceps aristatus (Dillwym, 1817). This bivalve, sometimes placed in the Lithophaga genus, is very similar, attends the same type of habitat, but is however smaller. 

The date of sea eats organic matter in suspension, which she collects using siphons. Its capacity of filtration (6 to 10 liters per day), is small compared with the mussel which filters ten times more of them ! She can grows up to 8 or 9 cm high. The period of reproduction starts in July-August (in spring and summer in the Adriatic), towards the end of the summer, when the temperature of water falls, during the white waters. The fixing of the larva on the substrate would be from the end of September to the beginning of November. The growth rate is very slow. Three years after fixing, the subject grows up only 1 cm. Its longevity would be 80 years.
In a healthy environmental context, the empty cavities of the lithophage date are colonized by a rich fauna made with annular polychetes and bryozoarias. Drilling is thus compensated by processes of bioconstruction of the rock, this fauna producing limestone tests. This bivalvular mollusc meets in all Mediterranean, in the Atlantic, from Portugal to Senegal, and in the north of Angola. Formerly she was sold on the provençaux markets at the same price as the caviar. Very appreciated, this species was the subject of an abusive collecting. However the method of fishing used (dynamite or underwater power pick) caused serious damage in the settlements of the rock substrates, which succeed, with the decree of the 26 novembre1992, to the prohibition of fishing and consumption in France of the european date mussel.

The seasweed
Posidonia oceanica (Linné)

Still called straw of sea, its name comes from the Greek god of the sea Poseidon. Of the family of Zosteraceas, Posidonia is a marine Phanerogama, i.e. a higher plant, with roots, a stem, sheets, flowers and fruits. The species Posidonia oceanica is an endemic species meeting only in the Mediterranean. Flowering, relatively rare, occurs in autumn and gives fruits called olives of sea which, after having been detached from the plant float and are failed on the beaches between May and June. The sheets, also little damageable, accumulate in litters or are rejected on the beaches during storms to form "benches". The rolled sheets can also form balls, called "aegagropiles". The meadows of Posidonias are the reference of the Mediterranean herbaria as regards habitat. The green thin straps which are on average 40 cm high have a protective role for innumerable species, using at the same time of shelter, food, spawning ground and place of laying.
Thanks to its chlorophyllian pigments and its extent, Posidonia produces a considerable quantity of oxygen. She is sensitive to the variations of water salinity, which explains why she is missing from brackish ponds or lagoons and proximities of mouth of rivers. The rhizome has a horizontal slow growth when it colonizes new environments and a vertical growth when the plant is gradually buried under the sediments trapped by the sheets. This phenomenon led to the formation of "mattes "(tangle of rhizomes which die gradually in the low part of the alive matte and posidonias in its higher part). The sheets tend to emerge and can give birth to barrier reefs like those of the Brusc or Port Cros. 

Posidonias which thus contributes to the oxygenation of sea water, meet from surface to 40 m. depth. They form a vast herbaria, thanks to their aptitude to colonize the sandy depths and the rock cracks where the sediments sufficiently accumulated. Although relatively tolerant with the variations in temperature, especially in surface waters, Posidonias need especially a particular substrate, avoiding at the same time, pure sands low in nutrients and the too muddy sediments with asphyxic character.

The growth of Posidonias is very slow because they are constantly exposed to the risks of pollution, the machines of seine and the constructions arranged in shore likely to modify the marine currents. When the herbaria decrease, it is all the fauna which elected there residence which is threatened. The actions of control of the cleansing and installations, taken in our region, made it possible to slow down this phenomenon of regression and to sometimes even reverse it. Posidonia oceanica is protected in France by decree from July 19, 1988.

Other protected Species