bottoms or be the predominant species on escarpments and in caves, it has also been
found as part of mixed forests associated with large gorgonians as an important
component of Mediterranean “coralligenous” assemblages. Furthermore, in the
deepest bathymetric levels, it may appear associated with the white coral communities (Freiwald et al. 2009; Taviani et al. 2010). In shallow waters (between about
15 and 70 m), C. rubrum colonies (most of them less than 5 cm tall) grow in caves,
crevices, overhangs and other protected interstices in crowded patches. In deeper
waters, between about 70 and 130 m, coral colonies tend to be larger and more
dispersed and typically settle on open surfaces. Below 130 m, colonies tend to be
even larger and less dense.
In the Alboran Sea, Corallium rubrum is a typical component of the deeper part
of the circalittoral rocky bottoms, and it is widespread in seamounts and rocky
outcrops, where reaches its maximum densities below 100 m depth. In the Alboran
Ridge, the red coral has been found mainly between 60 and 300 m (Templado et al.
2006; Gofas et al. 2014), and in the Seco de los Olivos, it has been found below
100 m (de la Torriente et al. 2014). In this area, shallow populations (15–50 m) of the
red coral are only known in the Strait of Gibraltar (López-González 1993; Ocaña
et al. 2009), while the presence of this species has not been detected in the Chafarinas
Islands.
Because of their high economic value, the precious red coral has been heavily
exploited in the Mediterranean Sea since ancient times. Its long history of intensive
commercial harvesting has resulted in a well-documented decline of its stocks
throughout the Mediterranean Sea, becoming especially apparent during the last
decades with clear evidence of overexploitation (Santangelo et al. 2010; Tsounis
et al. 2010). Due to this, several Mediterranean countries have developed national
legislation to regulate red coral fishing in their territorial waters or adopted the
regulations by the General Fisheries Commission for the Mediterranean (GFCM).
According to these recommendations, the populations (down to 50 m depth) should
be fully protected from exploitation, allowing their extremely slow recovery, and a
minimum harvest colony size (7 mm of colony basal diameter) corresponding to an
age of 30–35 years (Priori et al. 2013) should be established.
Regarding the Alboran Sea, the discovery in the mid-1980s of rich red coral
banks led to their uncontrolled harvesting and to a consequent rapid depletion by
fishermen from Sicily. Red coral was decimated by the usage of the so-called “Italian
bar”, a device formed by a heavy cross and tangle nets dragged over the bottom
(Santangelo et al. 2010). This prompted the Instituto Español de Oceanografía to
target cruises around the Alboran Island and Seco de los Olivos for evaluation of the
resource and the impact on it. The results of these researches were gathered in a
monographic volume of the Boletín Español de Oceanografia (1986) dedicated to
different topics on the red coral. In 1984, the Spanish government authorized four
fishing boats from Almería to extract coral on the Alboran Ridge using an “Italian
bar” modified under the control of researchers from IEO. This type of fishing proved
to be equally harmful to the environment and was banned in 1986. Since this date,
and for some years, the extraction of coral by divers was allowed down to 100 m. On
the other hand, at that time, the French-made submarine Nerée 201 was authorized to
10 Invertebrates: The Realm of Diversity
383
found as part of mixed forests associated with large gorgonians as an important
component of Mediterranean “coralligenous” assemblages. Furthermore, in the
deepest bathymetric levels, it may appear associated with the white coral communities (Freiwald et al. 2009; Taviani et al. 2010). In shallow waters (between about
15 and 70 m), C. rubrum colonies (most of them less than 5 cm tall) grow in caves,
crevices, overhangs and other protected interstices in crowded patches. In deeper
waters, between about 70 and 130 m, coral colonies tend to be larger and more
dispersed and typically settle on open surfaces. Below 130 m, colonies tend to be
even larger and less dense.
In the Alboran Sea, Corallium rubrum is a typical component of the deeper part
of the circalittoral rocky bottoms, and it is widespread in seamounts and rocky
outcrops, where reaches its maximum densities below 100 m depth. In the Alboran
Ridge, the red coral has been found mainly between 60 and 300 m (Templado et al.
2006; Gofas et al. 2014), and in the Seco de los Olivos, it has been found below
100 m (de la Torriente et al. 2014). In this area, shallow populations (15–50 m) of the
red coral are only known in the Strait of Gibraltar (López-González 1993; Ocaña
et al. 2009), while the presence of this species has not been detected in the Chafarinas
Islands.
Because of their high economic value, the precious red coral has been heavily
exploited in the Mediterranean Sea since ancient times. Its long history of intensive
commercial harvesting has resulted in a well-documented decline of its stocks
throughout the Mediterranean Sea, becoming especially apparent during the last
decades with clear evidence of overexploitation (Santangelo et al. 2010; Tsounis
et al. 2010). Due to this, several Mediterranean countries have developed national
legislation to regulate red coral fishing in their territorial waters or adopted the
regulations by the General Fisheries Commission for the Mediterranean (GFCM).
According to these recommendations, the populations (down to 50 m depth) should
be fully protected from exploitation, allowing their extremely slow recovery, and a
minimum harvest colony size (7 mm of colony basal diameter) corresponding to an
age of 30–35 years (Priori et al. 2013) should be established.
Regarding the Alboran Sea, the discovery in the mid-1980s of rich red coral
banks led to their uncontrolled harvesting and to a consequent rapid depletion by
fishermen from Sicily. Red coral was decimated by the usage of the so-called “Italian
bar”, a device formed by a heavy cross and tangle nets dragged over the bottom
(Santangelo et al. 2010). This prompted the Instituto Español de Oceanografía to
target cruises around the Alboran Island and Seco de los Olivos for evaluation of the
resource and the impact on it. The results of these researches were gathered in a
monographic volume of the Boletín Español de Oceanografia (1986) dedicated to
different topics on the red coral. In 1984, the Spanish government authorized four
fishing boats from Almería to extract coral on the Alboran Ridge using an “Italian
bar” modified under the control of researchers from IEO. This type of fishing proved
to be equally harmful to the environment and was banned in 1986. Since this date,
and for some years, the extraction of coral by divers was allowed down to 100 m. On
the other hand, at that time, the French-made submarine Nerée 201 was authorized to
10 Invertebrates: The Realm of Diversity
383