Jean-Georges Harmelin

Are the Mediterranean waters becoming warmer? Information from biological indicators

The authors are biologists specializing in benthos or ichthyofauna survey. They have worked in marine protected areas or in other littoral zones of the Mediterranean Sea for a long time. The use of SCUBA diving as a sampling method allows them a great knowledge of the benthos and ichthyofauna. Charles-Francois Boudouresque is vice-chairman of the Benthos Committee of the CIESM, and chairman of the scientific committees of the National Park of Port-Cros and of the Natural Regional Park of Corsica (marine reserve of Scandola). The other authors are members of these scientific committees

Microhabitat requirements for settlement of juvenile sparid fishes on Mediterranean rocky shores

Microhabitat attributes were characterized for recently settled juvenile fishes in six species of Sparidae (Diplodus annularis, D. puntazzo, D. sargus, D. vulgaris, Oblada melanura, and Sarpa salpa) on the rocky shore near Marseille, French Mediterranean coast. Depth, slope, type of substratum, biotic cover and hydrodynamic conditions were recorded wherever sparid recruits occurred. Juvenile Diplodus annularis settled in Posidonia oceanica seagrass beds at 5–8 m deep. The five other sparid species recruited in very shallow water (<2 m). D. puntazzo, D. sargus and D. vulgaris were observed in sites presenting a gentle slope with coarse sand, gravel, pebbles or boulders. Sarpa salpa was less dependent on slope for recruitment, but was always associated with macroalgae. Oblada melanura settlement occurred on rocky areas with various slopes, and was favoured by the presence of overhangs. When growing, juvenile sparids extended their home range vertically into deeper zones, and laterally in more exposed areas. Time partitioning in the use of suitable microhabitats for recruitment was observed for some species. Juveniles of Diplodus puntazzo and D. vulgaris shared the same sites from March to May, both exhibiting relatively low abundances. D. sargus recruited in far higher abundance in the same sites from May to September. Specific improvements in coastal man-made structures (harbours, artificial beaches) are suggested in order to increase the recruitment of some littoral fish species.

Hexactinellid cave, a unique deep-sea habitat in the scuba zone

Abstract Deep-sea organisms have colonized an unusual Mediterranean cave 18–24 m below the sea surface, in which the entrapment of a cold water mass results in stable temperature conditions throughout the year. These conditions, together with lack of light and limited food resources, approximate those of the deep Mediterranean. Among other deep-sea organisms, Oopsacas minuta , a representative of the bathyo-abyssal cold-water-adapted hexactinellid sponges, reproduces here yearround, making possible the first observations of larval behavior and ultrastructure on this phylogenetically important group of invertebrates. Easily accessible to scuba divers, this “bathyal island” in the littoral zone offers exceptional opportunities for deep-sea biology.

The littoral fish community of the Lebanese rocky coast (eastern Mediterranean Sea) with emphasis on Red Sea immigrants

The organisation of the coastal rocky fish community of Lebanon was investigated for the first time, using visual censuses. A total of 62 fish species were recorded between the surface and 32 m depth, 8 species being Red Sea migrants. Species richness and fish abundance were positively correlated first with substrate complexity and second with depth. The trophic structure of the community was dominated by diurnal zooplanktivores (Chromis chromis, Oblada melanura and Spicara smaris) and mesocarnivores 1 (Coris julis and Thalassoma pavo), and did not vary significantly with depth. The Lessepsian migrants represented 13% of the species richness and 19% of the total abundance of individuals. They dominated among herbivores, nocturnal zooplanktivores and macrocarnivores. The Lessepsian Siganus luridus and S. rivulatus (Siganidae), Pempheris vanicolensis (Pempheridae) and Sargocentron rubrum (Holocentridae) were now among the most common fish species on the Lebanese rocky coast. Lessepsian fish species displayed either similar ecological niches in the Red Sea and in the Levantine basin (P. vanicolensis, S. rubrum) or an enlargement of their depth distribution towards deeper waters in their new environment (S. luridus, S. rivulatus). This study will serve as a baseline for future studies as eastern Mediterranean communities are subjected to a steady increase in Red Sea migrant species.

Impact of Caulerpa taxifolia colonization on the littoral ichthyofauna of North-Western Mediterranean sea: preliminary results

After its accidental introduction in the French waters of the Mediterranean, the green seaweed Caulerpa taxifolia is now spreading along the coast of the Alpes-Maritimes, invading various biotopes (rock, sand and Posidonia oceanica seagrass beds). During the spring and fall of 1992, we evaluated the impact of C. taxifolia on the infralittoral ichthyofauna of Cap Martin (Menton) and compared invaded and reference sites, in shallow (3-8 m) and deep (11-25 m) stations.

Smittinidae (Bryozoa, Cheilostomata) from coastal habitats of Lebanon (Mediterranean sea), including new and non-indigenous species

Harmelin J.-G., Bitar G. & Zibrowius H. 2009. — Smittinidae (Bryozoa, Cheilostomata) from coastal habitats of Lebanon (Mediterranean sea), including new and non-indigenous species. Zoosystema 31 (1): 163-187. ABSTRACT The still poorly-known marine benthos of the Levant (warmest area of the Mediterranean) continuously undergoes changes due to the immigration of exotic species arriving from the Red Sea via the Suez canal, and likely from other tropical and subtropical regions via ship transport. The study of a large collection of bryozoans from the coastal zone (3–35 m) of Lebanon revealed the presence of seven species of Smittinidae belonging to two genera, Parasmittina Osburn, 1952 and Smittina Norman, 1903, whose morphological features and habitat requirements are described here in detail. Only two of these (P. raigii (Audouin, 1826) and P. rouvillei (Calvet, 1902)) were previously known from other Mediterranean areas. Parasmittina serruloides n. sp. and P. spondylicola n. sp., together with P. egyptiaca (Waters, 1909), are presumed to be Red Sea immigrants. The geographic distribution of P. profecta (Thornely, 1905) and S. nitidissima (Hincks, 1880), as well as their habitat in Lebanon and their capacity as fouling species strongly suggest that they are not indigenous to the Levant and that their source populations may be either in the Red Sea or in west Africa. However, alternative hypotheses are also conceivable, such as their persistence in the Levant area as relicts from former warm periods of the Mediterranean, or their existence as groups of sibling species with a more restricted geographical range.

Scorpiodinipora costulata (Canu & Bassler, 1929) (Bryozoa, Cheilostomata), a taxonomic and biogeographic dilemma: complex of cryptic species or human-mediated cosmopolitan colonizer?

ABSTRACT Despite implausible cosmopolitanism, the species Scorpiodinipora costulata (Canu & Bassler, 1929) has been attributed with reservations to small encrusting colonies with similar morphological features whose known distribution is scattered in tropical and subtropical seas: Pacific Ocean (Philippines), Indian Ocean (Oman), Red Sea, SE Mediterranean, SE Atlantic (Ghana) and SW Atlantic (Brazil). This material raised questions about its generic assignment. The genus Scorpiodinipora Balavoine, 1959 is redescribed with Schizoporella costulata Canu & Bassler, 1929, from the Philippines as the type species, as Balavoine misidentified the specimens to define the genus as Cellepora bernardii Audouin, 1826. Moreover, SEM examination of the cotypes of S. costulata showed that Canu & Bassler confused two genera among them. A lectotype and paralectotype were thus chosen from Canu & Basslers syntypes corresponding with the present morphotype. Hippodiplosia ottomuelleriana var. parva Marcus, 1938, from Brazil, which presents the same morphotype, is provisionally considered as the junior synonym of S. costulata. Considering the broad allopatric distribution of this morphotype across the oceans and the low capacity of dispersal of species with short-lived larvae, it is likely that this material includes several sibling species. However, the role of man-mediated dispersal is not excluded, at least in regions with high shipping activity, such as that comprising the Suez Canal.

Les depots d'enduits manganoferriferes en environnement marin littoral; l'exemple de grottes sous-marines en Mediterranee nord-occidentale

Black coating of hard substrates by Mn and Fe oxides has long been reported from shallow, dark, submarine caves. However, these littoral metallic deposits have never been studied in detail, despite expected analogies with deep-sea polymetallic crusts. Submarine caves are characterized by darkness and low rates of exchanges with the open sea. Lack of primary production and confinement of inner water bodies result in marked oligotrophy and extremely reduced biomass, i.e. conditions close to those prevailing in deep-sea habitats. Field evidences suggested that the formation of Mn-Fe coatings was closely tied to these particular environmental conditions. The goal of this study was to examine the detailed features of Mn-Fe coatings from dark caves with different local conditions, and to try to identify the processes responsible for their deposition. Study sites and methods: Three sublittoral, single-entrance, caves were sampled by scuba diving along the coasts of Provence (France, Mediterranean Sea). The first site is a large karstic cave (Tremies Cave, 16 m depth at entrance floor, 60 m long; Marseille-Cassis area) with an ascending profile which results in a buffered thermal regime and markedly oligotrophic conditions due to warm water trapping in its upper part. Wall fragments were sampled at 30 m (medium confinement: zone B) and 60 m (strong confinement: zone C) from the cave entrance. The second site is a large tubular cavity open in conglomerate formations (3PP Cave, 15 m depth at entrance floor, 120 m long; La Ciotat) with a descending profile which results in relative permanence of winter temperatures within the inner parts, complex water circulation and presumed greater input of sedimented particles than in the preceding cave. Wall samples were taken at 25 m, 70 m and 100 m from entrance. The third site is a small, horizontal, cave open in quartzite formations (Bagaud Cave, 7 m depth at entrance floor, about 10 m long; WNW of Port-Cros Island, bay of Hyeres). Sampling was performed on walls of a narrow corridor between an anterior room and a smaller inner room. A sporadic outflow of continental waters is located in the inner room. The samples were preserved in 50% ethylic alcohol or studied soon after their sampling. Before carbon coating and SEM examination, or microanalyses with SEM-associated spectrometers, they were treated in a 33% Chlorox solution and thereafter washed in demineralized water and dried. Micromorphology: At low-medium magnification (

Effects of Artificial Reef Design on Associated Fish Assemblages in the Côte Bleue Marine Park (Mediterranean Sea, France)

The Cote Bleue marine park, located east of Marseille (Fig. 1) was created in 1983 with the objectives of promotion (increasing public awareness) of the marine system, protection of the natural environment and the preservation of traditional fisheries. An artificial reef programme was initiated in 1983, with the deployment of 225 m3 of experimental artificial reefs, made from bricks and breeze blocks. Since 1985 the programme has continued using industrially made concrete reefs. Two types of small cubic modules (Fig. 2) have been used: 1.7 m3 (390 units) and 2 m3 (90 units). These CARU modules (cubic artificial reef units) have been arranged in piles of 20-120 m3 (Fig. 3). Eight 158 m3 volume modules (LARU; large artificial reef unit, Figs. 2 and 3) were individually placed near the CARU reefs. The whole programme comprised 2332 m3 of artificial reef deployed in three sites of the marine park. Most of these reefs are open to fishing. This programme was financed by several organizations (UE-FEOGA, France, Region Provence-Alpes Cote d’Azur, Departement des Bouches-du-Rhone and towns associated with the marine park management). Investments made between 1985 and 1989 reached around FF 1 700 000 (average reef cost: FF 510 m−3).

Re-shifting the ecological baseline for the overexploited Mediterranean red coral

Overexploitation leads to the ecological extinction of many oceanic species. The depletion of historical abundances of large animals, such as whales and sea turtles, is well known. However, the magnitude of the historical overfishing of exploited invertebrates is unclear. The lack of rigorous baseline data limits the implementation of efficient management and conservation plans in the marine realm. The precious Mediterranean red coral Corallium rubrum has been intensively exploited since antiquity for its use in jewellery. It shows dramatic signs of overexploitation, with no untouched populations known in shallow waters. Here, we report the discovery of an exceptional red coral population from a previously unexplored shallow underwater cave in Corsica (France) harbouring the largest biomass (by more than 100-fold) reported to date in the Mediterranean. Our findings challenge current assumptions on the pristine state of this emblematic species. Our results suggest that, before intense exploitation, red coral lived in relatively high-density populations with a large proportion of centuries-old colonies, even at very shallow depths. We call for the re-evaluation of the baseline for red coral and question the sustainability of the exploitation of a species that is still common but ecologically (functionally) extinct and in a trajectory of further decline.