Name of Site: Zona fil-Bahar Bejn Rdum Majjiesa u Ras ir-Raheb
Year of Natura 2000 designation: 2008
Annex 1 Protected Habitats:
- 1110 Sandbanks which are slightly covered by sea water all the time
- 1120 Posidonia beds (Posidonion oceanicae)
- 1170 Reefs
- 8330 Submerged or partially submerged sea caves
A rich and diverse biota can be found in the Rdum Majjiesa to Ras ir-Raheb marine area, complementing its geo-morphological characteristics. The site hosts representatives of the main marine habitat types occurring in the Maltese Islands, with the associated biotic assemblages including species and ecosystems of conservation importance.
Meadows of the seagrass Posidonia oceanica dominate large areas of the seabed within the 50 metre bathymetric region. These meadows are found in different ecomorphosis, on bedrock and on sand, where some areas produce thick matte walls allowing for colonisation by an array of photophilic algae. Posidonia oceanica meadows support a large variety of organisms of conservation interest, such as the bivalve Pinna nobilis, species of economic importance, such as Octopus vulgaris, as well as a number of demersal fish
species. The seagrass Cymodocea nodosa is also very abundant in the site, where its meadows are among the most extensive around the Maltese Islands. C. nodosa forms a major association with the biocoenosis of fine sands, but has also been recorded on Blue Clay and Globigerina bedrock covered by thin layers of silt.
Phaeophytes cover a high percentage of the hard substrata in the site, with the commonest species being Cystoseira spinosa var. tenuior, particularly in the shallower depths.
At depths greater than 15 meters, associations of Dictyopteris polypodioides, Cystoseira squarrosa and Sargassum vulgare become more dominant. Hard substrata such as drop-offs and cave walls are characterised by sciaphilic assemblages dominated by assemblages of Flabellia petiolata, Halimeda tuna and Peyssonnelia sp., with other rhodophytes, calcareous algae and hydroids being also abundant. The extensive sandbanks found in inlets along the coast
and beyond the seagrass meadows of the site, support a diverse epifauna, mostly echinoderms and endobiotic species that leave their traces by the numerous burrows on the sand surface. The variety of marine habitats found in the site provides important feeding, breeding and nursing grounds for many fish species, including demersal and predatory types. The rocky reefs and drop-offs attract shoals of large fish, such as Sphyraena sphyraena and Seriola dumerili; as well as solitary species like the Epinephelus marginatus and Dasyatis spp.