12. Jul, 2016

The Mediterranean: damaged but not lost.

In the French Mediterranean lies a chain of islands, 15 miles south of  the coastline of the towns of Hyeres and Le Lavandou (see picture at left). The French gave it the poëtical name   Les Isles d’Or (Golden Islands).*  They consist  of three big islands  Porquerolles, Port Cros and I’le du Levant and a couple of smaller rocky ‘satellite’  islands:  I., Gabaud, I. Rascas and I.Gabiniere around Port Cros*.  

Parc national The area  around Port Cros (encircled in green, at the right) was declared a French National park in 1963 on the initiative of Philip Tailliez, a friend of Cousteau. The state  is now the sole owner. Later, a part of the bigger island Porquerolles was included in the National Park (also encircled in green, at the left). Diving tourism is booming in the summer months  when you will find numerous boats along the peninsula of Giens (upper left in picture)  as well as the smaller  islands of the national park.

Weather In the summer the weather is dominated by a south-westerly wind  that normally comes with  sunny weather and  an agreeable temperature running in the 80ties. But occasionally,  a cold and fierce wind, the Mistral drops in after a depression. The Mistral arises in the high pressure Central Plateau in the middle of France and  then forces itself southwardly trough the Rhone valley until it reaches the low pressure Mediterranean sea  near Marseille. In then spreads out sidewards to follow the Eastern and Western coastlines, gradually losing its force. The dry and cold  mountain air of the Mistral leads to a cloudless  blue sky and a temperature drop of the air, as well as the water, when turbulence mixes warmer surface water with deeper colder water.

Wrecks. There are several wrecks to visit in this area. To name just a few: the Donator ( or: Prosper Schiaffino, depth 45 m,), the Michel C (35 m) and Le Grec (45 m). Diving to the wrecks  is only possible with a calm sea, and one must always be aware of currents and the depth of their locations, which bring divers easily within the decompression zone.**

Ecology Despite the beauty of its rocky and fertile coastline, the Mediterranean is a relatively poor sea. Cousteau already wrote ‘La Méditerranee est belle mais pauvre’***.  This holds for  its fish colonies that cannot  compare with those of  the Atlantic as well as the amount of nutrients in the water.  An  ecosystem that  can survive in these conditions  is called oligotrophic:  this implies a slow growth and rate of metabolism of organisms, and  a low density of  the fish populations. In the past coastal waters and beaches near the bigger cities of Corsica as well as the Cote d'Azur suffered from pollution from the sewers that dumpted their content directly in the sea. Luckily, this has been improved some 30 years ago.  The presence of the sea grass fields of Posidonia oceanica is often considered as an index of the health of the Mediterranean. One estimates that the size of these fields has been reduced with around 20% in the last century by water pollution and boats anchoring in  coastal areas.

Overfishing has also threatened  larger fishes. An example is the Dusky  grouper (Epinephelus marginatus; see  https://en.wikipedia.org/wiki/Epinephelus_marginatus  ) that is still considered an endangered species in the Mediterranean, especially in Spain. The Dusky grouper is a protogynous hermaphrodite, i.e. the young are predominantly female but transform into males as they grow larger.  But since it is also  a favorite dish on Mediterranean  tables, they have been hunted down without mercy both by  fishermen and spear gun adepts so that  only few were left  the 70ties. One of the blessings of  the National park  of Port Cros was the miraculous come-back of grouper colonies, that now comprise several  hundreds individuals. Occasionally they  even show along the protruding points of the Peninsula of Giens. I managed to bring in some groupers very close to the front of the camera by using my PCD (Personal Chumming Device).****  The idea is to squirt a small cloud of chum in the water, only about 10 cm wide, but sufficient to stimulate the grouper's refined olfactory system even when its still some meters  away.  After a couple of dives they will approach you even without using the PCD. One should be aware  however that using this gadget in areas where baiting is prohibited may still be considered as an offence.

Variety of species.  In the Mediterranean you will not find the  variety of hard and soft corals found in its neighbor, the warmer  Red Sea. It does however have its own ‘specialties’: colonies of yellow anemones (Parazoanthus axinellae) often found on cave walls, and Gorgonians like Paramuricea clava and Eunicella verrucosa, mostly at walls exposed to a current. In shallower waters near the coast one will  still find the sea grass fields of Posidonia oceanica, often a hiding place for the cuttlefish (Sepia officinalis), the red anemone Actinia equina (Beadlet anemone) and Anemonia sulcata ('spaghetti anemone') in the intertidal zones.  The bigger Ceriantus membranaceus, a large solitary anemone can be found on deeper and muddy sandy floors.  Its polyps detract rapidly into its tube if you get too close. And then there is the tube worm Spirograph spallanzani with its  beautiful spiral crown, another favorite target for close up fotographers.  

Around the smaller islands of the park like Gabiniere you can occasionally meet schools of the barracuda (Sphyraena sphyraena). And there are numerous  smaller fish along the walls and crevices of the islands. Here a selection of species that you can still see when you dive regularly in the area *****. Mullets (Mullus barbatus and surmuletus, rouget in French), moray eel (Muraena helena), scorpionfish (Rascasse: red: Scorpaena scrofa,  brown: Scorpaena porcus), wrasses like the rainbow wrasse (Coris Julis),  peacock wrasse (Thalasoma pavo) and Crenilabrus, the lovely Anthias  anthias, the little black damselfish (Chromis chromis), several species of blennies mostly in shallow rocky areas, schools of smaller sea breams Diplodus vulgaris and sargus,  Sarpa salpa, the bigger Dentex, and of course the Octopus vulgaris.**** To name just a few species that were part of the original Mediterranean biotopes, and have now returned in greater number in areas protected from pollution and overfishing.  Difficult to spot but  present in the area are rays, the ovipari dogfish (Scyliorhinus; rousette in French) and dolphins. Some 30 years ago Cousteau spoke of the Mediterranean as the ‘wounded sea’ ( La Mer Blessée)***. But it is good to learn that the damage of Mediterranean sea caused by human neglect can be repaired by human care. At some locations this has even resulted in a return of the former paradise.   




***J.Y.Cousteau, Y. Paccalet (1987). La Mer Blessée. Flammarion.


*****The Hamlyn Guide to the Flora and Fauna of the Mediterranean Sea. 1982. A.C. Campbell. Hamlyn, London.