echinoderms Astropecten irregularis, Amphiura spp., Oestergrenia digitata and
Ocnus planci (Cano and García 1982; Moya-Urbano et al. 2016). Muddy sediments
generally occur at greater depths, and their high organic content promotes higher
abundances of deposit feeders, representing an important variable explaining the
distribution of the benthic communities (Marina et al. 2015; Díaz et al. 2017).
In these types of circalittoral soft bottoms, some habitat-forming species such as
sea pens (Veretillum, Pennatula) and gorgonians (Spinimuricea cf. atlantica) provide hard substrate and food for other invertebrates (e.g. Armina maculata feeding
on Veretillum cynomorium) (Gofas et al. 2011). Nevertheless, the sessile habitatforming species are suffering impacts from trawlers and have declined during
decades. They sometimes display higher abundances close to rocky bottoms where
they are protected from trawling (Gofas et al. 2014a).
Although temporal changes have been poorly studied in circalittoral bottoms and
thought to be less acute than in infralittoral bottoms, Díaz et al. (2017) detected a
higher abundance of benthic and demersal cephalopods (e.g. Octopus vulgaris,
Sepia spp.) in autumn and winter in the circalittoral bottoms of the bay of Málaga.
The circalittoral muddy bottoms of the Alboran Sea are not encompassed by any
specific regulation for their protection. They are in general exposed to a higher
trawling activity than the bathyal ones due to their proximity to the fishing ports, and
this may have produced continued impacts on the habitat-forming species such as the
sea pens. The OSPAR Convention recognizes “Sea-pen and burrowing megafauna
communities” among the list of threatened and declining habitats, and although
outside the scope of this Convention, this should be taken into account to promote
some kind of status within the Mediterranean Sea.
9.7 Deep-Sea Communities
In the Alboran Sea, the bathyal level, ranging from the edge of the continental shelf
to the deepest part of the basin, features a broad diversity of benthic communities.
The deep-sea benthic communities of the region are strongly influenced by the
peculiar oceanographic setting in which the superficial Atlantic Water (AW), with
a high level of primary productivity, flows within the first 200 m above the outgoing
Levantine Intermediate Water (LIW). These communities are also influenced by
their geographical location, resulting in the overlap of Mediterranean fauna and
typical “Atlantic” species (Gofas et al. 2014b).
9.7.1 Bathyal Hard Bottoms
Bathyal hard-bottom communities are patchily distributed over the heterogeneous
and complex topography of the Alboran Sea basin and are restricted to prominent
geomorphological features, such as seamounts, coral mounds, canyons and ridges
9 Benthic Fauna of Littoral and Deep-Sea Habitats of the Alboran Sea: A. . .
335
Ocnus planci (Cano and García 1982; Moya-Urbano et al. 2016). Muddy sediments
generally occur at greater depths, and their high organic content promotes higher
abundances of deposit feeders, representing an important variable explaining the
distribution of the benthic communities (Marina et al. 2015; Díaz et al. 2017).
In these types of circalittoral soft bottoms, some habitat-forming species such as
sea pens (Veretillum, Pennatula) and gorgonians (Spinimuricea cf. atlantica) provide hard substrate and food for other invertebrates (e.g. Armina maculata feeding
on Veretillum cynomorium) (Gofas et al. 2011). Nevertheless, the sessile habitatforming species are suffering impacts from trawlers and have declined during
decades. They sometimes display higher abundances close to rocky bottoms where
they are protected from trawling (Gofas et al. 2014a).
Although temporal changes have been poorly studied in circalittoral bottoms and
thought to be less acute than in infralittoral bottoms, Díaz et al. (2017) detected a
higher abundance of benthic and demersal cephalopods (e.g. Octopus vulgaris,
Sepia spp.) in autumn and winter in the circalittoral bottoms of the bay of Málaga.
The circalittoral muddy bottoms of the Alboran Sea are not encompassed by any
specific regulation for their protection. They are in general exposed to a higher
trawling activity than the bathyal ones due to their proximity to the fishing ports, and
this may have produced continued impacts on the habitat-forming species such as the
sea pens. The OSPAR Convention recognizes “Sea-pen and burrowing megafauna
communities” among the list of threatened and declining habitats, and although
outside the scope of this Convention, this should be taken into account to promote
some kind of status within the Mediterranean Sea.
9.7 Deep-Sea Communities
In the Alboran Sea, the bathyal level, ranging from the edge of the continental shelf
to the deepest part of the basin, features a broad diversity of benthic communities.
The deep-sea benthic communities of the region are strongly influenced by the
peculiar oceanographic setting in which the superficial Atlantic Water (AW), with
a high level of primary productivity, flows within the first 200 m above the outgoing
Levantine Intermediate Water (LIW). These communities are also influenced by
their geographical location, resulting in the overlap of Mediterranean fauna and
typical “Atlantic” species (Gofas et al. 2014b).
9.7.1 Bathyal Hard Bottoms
Bathyal hard-bottom communities are patchily distributed over the heterogeneous
and complex topography of the Alboran Sea basin and are restricted to prominent
geomorphological features, such as seamounts, coral mounds, canyons and ridges
9 Benthic Fauna of Littoral and Deep-Sea Habitats of the Alboran Sea: A. . .
335