in this area. A major anthropogenic impact on Mediterranean rhodolith beds is due to
otter trawling (Barberá et al. 2003; Bordehore et al. 2003, and references therein).
“Maërl”/rhodolith beds constitute a very vulnerable habitat, due to the slow growth
rate of their components, low reproductive potential and the long time of
regeneration.
9.6.5 Coastal Terrigenous Mud
This kind of bottom can be found already in the infralittoral zone, particularly in bays
or inlets under the influence of rivers, which supply terrigenous fine sediments and
cover extensive areas of the continental shelf (Pérès and Picard 1964). The percentage of mud is high, and most of it is of inorganic origin; therefore the percentage of
organic matter is moderate.
Characteristic species of shallow muddy bottoms of the littoral of Málaga are
molluscs such as the tropical West African gastropod Tritia elata and the bivalve
Spisula subtruncata. Chamelea striatula can reach high densities and replaces
Chamelea gallina where the mud content increases. Some species are associated
with cnidarians, such as the rare architectonicid Basisulcata lepida. Regarding
crustaceans, the pagurids are also dominant, such as Anapagurus breviaculeatus,
A. petiti, Pagurus excavatus, P. cuanensis and P. prideaux (García Raso et al. 2010).
Sea pens such as Veretillum cynomorium, Pteroides griseum and Cavernularia
pusilla may occur, although more commonly found in deeper parts of the continental
shelf. Among the echinoderms, the brittle star Acrocnida brachiata is common in
this type of bottom. Besides, the aquaculture of the mussel Mytilus galloprovincialis
in the infralittoral of southern Spain has been a great expansion in the last decades
(Tirado et al. 2011), and suspended mussel cultures generate large amounts of mud
under the rafts, promoting the onset of this type of assemblage.
Benthic communities of circalittoral muddy sand bottoms are generally dominated by different cnidarians (Epizoanthus arenaceus), molluscs (the gastropods
Alvania testae, Sorgenfreispira brachystoma, Turritella communis, T. mediterranea
and Bivetiella similis and the bivalves Saccella commutata, Chamelea striatula,
Timoclea ovata), annelids (Hyalinoecia tubicola, Ditrupa arietina), decapods
(Plesionika heterocarpus, Philocheras bispinosus, Anapagurus alboranensis,
Processa canaliculata, P. nouveli and Galathea spp.) and echinoderms (Astropecten
irregularis, Paraleptopentacta tergestina, Ophiocten affinis) (Marina et al. 2015;
Moya-Urbano et al. 2016).
Some of these species can also occur on more fully muddy bottoms, in which the
community is composed by the cnidarians Veretillum cynomorium, Cavernularia
pusilla, Pennatula rubra, Alcyonium palmatum and Cerianthus membranaceus; the
annelids Spiochaetopterus cf. costarum and Sternaspis scutata; the gastropods Tritia
ovoidea and Turritella communis; the bivalves Tellina compressa, Nucula sulcata,
Abra alba, A. nitida, Chamelea striatula and Venus nux; the decapods Philocheras
bispinosus, Goneplax rhomboides, Alpheus glaber and Inachus dorsettensis; and the
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otter trawling (Barberá et al. 2003; Bordehore et al. 2003, and references therein).
“Maërl”/rhodolith beds constitute a very vulnerable habitat, due to the slow growth
rate of their components, low reproductive potential and the long time of
regeneration.
9.6.5 Coastal Terrigenous Mud
This kind of bottom can be found already in the infralittoral zone, particularly in bays
or inlets under the influence of rivers, which supply terrigenous fine sediments and
cover extensive areas of the continental shelf (Pérès and Picard 1964). The percentage of mud is high, and most of it is of inorganic origin; therefore the percentage of
organic matter is moderate.
Characteristic species of shallow muddy bottoms of the littoral of Málaga are
molluscs such as the tropical West African gastropod Tritia elata and the bivalve
Spisula subtruncata. Chamelea striatula can reach high densities and replaces
Chamelea gallina where the mud content increases. Some species are associated
with cnidarians, such as the rare architectonicid Basisulcata lepida. Regarding
crustaceans, the pagurids are also dominant, such as Anapagurus breviaculeatus,
A. petiti, Pagurus excavatus, P. cuanensis and P. prideaux (García Raso et al. 2010).
Sea pens such as Veretillum cynomorium, Pteroides griseum and Cavernularia
pusilla may occur, although more commonly found in deeper parts of the continental
shelf. Among the echinoderms, the brittle star Acrocnida brachiata is common in
this type of bottom. Besides, the aquaculture of the mussel Mytilus galloprovincialis
in the infralittoral of southern Spain has been a great expansion in the last decades
(Tirado et al. 2011), and suspended mussel cultures generate large amounts of mud
under the rafts, promoting the onset of this type of assemblage.
Benthic communities of circalittoral muddy sand bottoms are generally dominated by different cnidarians (Epizoanthus arenaceus), molluscs (the gastropods
Alvania testae, Sorgenfreispira brachystoma, Turritella communis, T. mediterranea
and Bivetiella similis and the bivalves Saccella commutata, Chamelea striatula,
Timoclea ovata), annelids (Hyalinoecia tubicola, Ditrupa arietina), decapods
(Plesionika heterocarpus, Philocheras bispinosus, Anapagurus alboranensis,
Processa canaliculata, P. nouveli and Galathea spp.) and echinoderms (Astropecten
irregularis, Paraleptopentacta tergestina, Ophiocten affinis) (Marina et al. 2015;
Moya-Urbano et al. 2016).
Some of these species can also occur on more fully muddy bottoms, in which the
community is composed by the cnidarians Veretillum cynomorium, Cavernularia
pusilla, Pennatula rubra, Alcyonium palmatum and Cerianthus membranaceus; the
annelids Spiochaetopterus cf. costarum and Sternaspis scutata; the gastropods Tritia
ovoidea and Turritella communis; the bivalves Tellina compressa, Nucula sulcata,
Abra alba, A. nitida, Chamelea striatula and Venus nux; the decapods Philocheras
bispinosus, Goneplax rhomboides, Alpheus glaber and Inachus dorsettensis; and the
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J. L. Rueda et al.