ochroleuca is included in Annex I of the Berne Convention (strictly protected flora
species) only for its Mediterranean populations. The status of kelp forests is not
better in the Atlantic, where they are more widespread but where Norway, Iceland,
Denmark, Ireland and the European Commission have strongly opposed at OSPAR’s
Biodiversity Committee, Berlin, March 6–10, 2017, the inclusion of kelp forests in
the List of Threatened and/or Declining Species and Habitats.
9.4.4 Infralittoral Hard Bottoms Dominated by Sessile
Invertebrates
Calcareous bio concretion structures are often developed under dim-light conditions
by sciaphilous algae and other habitat-forming invertebrates, providing highly
structured environments which, in turn, support a wide range of other sessile and
mobile species (Ballesteros 2006). These biotic assemblages are more extensive at
circalittoral depths of the Alboran Sea (Giakoumi et al. 2013), although they can be
found as enclaves in the infralittoral zone under crevices and overhangs or at the
entrance of marine caves.
This so-called pre-coralligenous community dominated by sessile invertebrates
has been described both in the southern and northern areas of the Alboran Sea
(e.g. Chafarinas Islands, Cap des Trois Fourches, Al Hoceima, Alboran Island, coast
of Granada, the “Laja del Almirante” in the Calahonda Special Area of Conservation, Málaga). This habitat harbours sciaphilous coralline algae (e.g. species of the
genera Mesophyllum, Lithophyllum), bryozoans (e.g. Pentapora fascialis,
Myriapora truncata), polychaetes (e.g. Salmacina dysteri), sponges (Oscarella
lobularis, Reniera spp., Crambe crambe, Clathrina spp., Axinella spp., Ircinia
spp., Aplysina cavernicola, etc.), cnidarians (Astroides calycularis, Eudendrium
racemosum, Alcyonium spp., Eunicella spp.) and echinoderms or ascidians
(Aplidium conicum, Didemnum spp., Halocynthia papillosa) among others (PérezRuzafa and López-Ibor 1988; Cebrián and Ballesteros 2004; Franzosini and Limam
2004; Sánchez-Tocino et al. 2009; García Raso et al. 2010; Bazairi et al. 2013).
Exceptionally shallow occurrences of the gorgonian Ellisella paraplexauroides were
recorded around the Chafarinas Islands by Maldonado et al. (2013) (see Chap. 10).
Along the coast of Granada, in the northern part of the Alboran Sea, these
communities are characterized by a dominance of suspension feeders and higher
biomass of calcium carbonate than in other temperate and Mediterranean sites
(Cebrián et al. 2000; Cebrián & Ballesteros 2004). This pattern, together with its
high diversity of species, seems influenced by the particular hydrodynamic conditions within this area (mixing of Atlantic and Mediterranean waters and the occurrence of upwelling events). Although they were not exclusive of coralligenous
communities, many mobile species (some of them protected) are commonly associated with these sciaphilous environments. Among them are molluscs (Luria lurida,
Naria spurca), decapods (Scyllarides latus, Scyllarus arctus, Palinurus elephas),
9 Benthic Fauna of Littoral and Deep-Sea Habitats of the Alboran Sea: A. . .
311
species) only for its Mediterranean populations. The status of kelp forests is not
better in the Atlantic, where they are more widespread but where Norway, Iceland,
Denmark, Ireland and the European Commission have strongly opposed at OSPAR’s
Biodiversity Committee, Berlin, March 6–10, 2017, the inclusion of kelp forests in
the List of Threatened and/or Declining Species and Habitats.
9.4.4 Infralittoral Hard Bottoms Dominated by Sessile
Invertebrates
Calcareous bio concretion structures are often developed under dim-light conditions
by sciaphilous algae and other habitat-forming invertebrates, providing highly
structured environments which, in turn, support a wide range of other sessile and
mobile species (Ballesteros 2006). These biotic assemblages are more extensive at
circalittoral depths of the Alboran Sea (Giakoumi et al. 2013), although they can be
found as enclaves in the infralittoral zone under crevices and overhangs or at the
entrance of marine caves.
This so-called pre-coralligenous community dominated by sessile invertebrates
has been described both in the southern and northern areas of the Alboran Sea
(e.g. Chafarinas Islands, Cap des Trois Fourches, Al Hoceima, Alboran Island, coast
of Granada, the “Laja del Almirante” in the Calahonda Special Area of Conservation, Málaga). This habitat harbours sciaphilous coralline algae (e.g. species of the
genera Mesophyllum, Lithophyllum), bryozoans (e.g. Pentapora fascialis,
Myriapora truncata), polychaetes (e.g. Salmacina dysteri), sponges (Oscarella
lobularis, Reniera spp., Crambe crambe, Clathrina spp., Axinella spp., Ircinia
spp., Aplysina cavernicola, etc.), cnidarians (Astroides calycularis, Eudendrium
racemosum, Alcyonium spp., Eunicella spp.) and echinoderms or ascidians
(Aplidium conicum, Didemnum spp., Halocynthia papillosa) among others (PérezRuzafa and López-Ibor 1988; Cebrián and Ballesteros 2004; Franzosini and Limam
2004; Sánchez-Tocino et al. 2009; García Raso et al. 2010; Bazairi et al. 2013).
Exceptionally shallow occurrences of the gorgonian Ellisella paraplexauroides were
recorded around the Chafarinas Islands by Maldonado et al. (2013) (see Chap. 10).
Along the coast of Granada, in the northern part of the Alboran Sea, these
communities are characterized by a dominance of suspension feeders and higher
biomass of calcium carbonate than in other temperate and Mediterranean sites
(Cebrián et al. 2000; Cebrián & Ballesteros 2004). This pattern, together with its
high diversity of species, seems influenced by the particular hydrodynamic conditions within this area (mixing of Atlantic and Mediterranean waters and the occurrence of upwelling events). Although they were not exclusive of coralligenous
communities, many mobile species (some of them protected) are commonly associated with these sciaphilous environments. Among them are molluscs (Luria lurida,
Naria spurca), decapods (Scyllarides latus, Scyllarus arctus, Palinurus elephas),
9 Benthic Fauna of Littoral and Deep-Sea Habitats of the Alboran Sea: A. . .
311