could be an alternative nowadays. There is a hatchery in Andalusia, and despite the
fact that young fish prefer temperatures over 25
C, some studies (DIVERSIFY
2018a) have shown that fish greater than 350 g grow at a higher rate at temperatures
between 21 and 23
C. Meagre (Argyrosomus regius) is another species that could be
cultured in this area. There are some hatcheries close to the Alboran Sea, and,
according to some authors (DIVERSIFY 2018b), it seems that temperatures above
25
C could be detrimental for growth and feeding conversion rate. More than that,
some pathological problems affecting amberjack (ciliated parasites like
Cryptocaryon irritans and monogenea trematodes like Neobenedenia and Zeuxapta)
and meagre (systematic granulomatosis) could be more harmful at higher temperatures in summer.
Atlantic bluefin tuna could also be an option since, besides the cages placed in
Ceuta in 1979, a couple of farms have been running in Cadiz and Almeria, only a few
miles away from the Alboran Sea. In 2018, a facility in Barbate (Cadiz) fattened
more than 1100 Tm of tuna. There are not any technical problems in this semiculture,
the only drawback is to transport tunas from Almadrabas in Cadiz, where tunas are
captured, to the Alboran Sea through the Strait of Gibraltar.
Apart from these considerations, aquaculture of some fish from colder waters could
be considered, and, in this sense, the culture of emerging species like the blackspot sea
bream, Pagellus bogaraveo, and maybe first stages of ongrowing of wreckfish,
Polyprion americanus, could be an interesting alternative in the next future.
As it has been stated before, a land-based facility for pre-ongrowing of sea bass
and sea bream is running in this area. Pre-ongrowing is needed for cage development
so that fish are usually introduced in the cages when they are 10–20 g on average,
and these facilities could be useful for nearby cages.
By the last, sole could also be a candidate to be cultured in land-based facilities, as it
was demonstrated some years ago. In both land-based facilities, recirculating aquaculture systems (RAS) could improve the obtained results, keeping good-quality water
as well as an adequate temperature during all the culture. In addition, facilities with
RAS techniques are considered to be less detrimental to the environment.
20.3.2 Mollusk
20.3.2.1 Bivalve Mollusk
The culture of bivalve mollusks in the Alboran Sea is undertaken extensively, through
the capture of postlarval stage and their fattening to commercial size. The whole
farming cycle takes place mainly in the open sea, since there are few sheltered areas. In
addition, due to the strong demographic pressure that exists in the area, there are
increasingly fewer freely available areas to install facilities to culture mollusk.
Experiments have been carried out in the Alboran Sea to determine the viability
of the culture of mussel (Mytilus galloprovincialis), banded carpet shell (Venerupis
rhomboids), and three members of pectinids: king scallop (Pecten maximus), black
scallop (Mimachlamys varia), and queen scallop (Aequipecten opercularis). Studies
670
A. Ortega et al.
fact that young fish prefer temperatures over 25
C, some studies (DIVERSIFY
2018a) have shown that fish greater than 350 g grow at a higher rate at temperatures
between 21 and 23
C. Meagre (Argyrosomus regius) is another species that could be
cultured in this area. There are some hatcheries close to the Alboran Sea, and,
according to some authors (DIVERSIFY 2018b), it seems that temperatures above
25
C could be detrimental for growth and feeding conversion rate. More than that,
some pathological problems affecting amberjack (ciliated parasites like
Cryptocaryon irritans and monogenea trematodes like Neobenedenia and Zeuxapta)
and meagre (systematic granulomatosis) could be more harmful at higher temperatures in summer.
Atlantic bluefin tuna could also be an option since, besides the cages placed in
Ceuta in 1979, a couple of farms have been running in Cadiz and Almeria, only a few
miles away from the Alboran Sea. In 2018, a facility in Barbate (Cadiz) fattened
more than 1100 Tm of tuna. There are not any technical problems in this semiculture,
the only drawback is to transport tunas from Almadrabas in Cadiz, where tunas are
captured, to the Alboran Sea through the Strait of Gibraltar.
Apart from these considerations, aquaculture of some fish from colder waters could
be considered, and, in this sense, the culture of emerging species like the blackspot sea
bream, Pagellus bogaraveo, and maybe first stages of ongrowing of wreckfish,
Polyprion americanus, could be an interesting alternative in the next future.
As it has been stated before, a land-based facility for pre-ongrowing of sea bass
and sea bream is running in this area. Pre-ongrowing is needed for cage development
so that fish are usually introduced in the cages when they are 10–20 g on average,
and these facilities could be useful for nearby cages.
By the last, sole could also be a candidate to be cultured in land-based facilities, as it
was demonstrated some years ago. In both land-based facilities, recirculating aquaculture systems (RAS) could improve the obtained results, keeping good-quality water
as well as an adequate temperature during all the culture. In addition, facilities with
RAS techniques are considered to be less detrimental to the environment.
20.3.2 Mollusk
20.3.2.1 Bivalve Mollusk
The culture of bivalve mollusks in the Alboran Sea is undertaken extensively, through
the capture of postlarval stage and their fattening to commercial size. The whole
farming cycle takes place mainly in the open sea, since there are few sheltered areas. In
addition, due to the strong demographic pressure that exists in the area, there are
increasingly fewer freely available areas to install facilities to culture mollusk.
Experiments have been carried out in the Alboran Sea to determine the viability
of the culture of mussel (Mytilus galloprovincialis), banded carpet shell (Venerupis
rhomboids), and three members of pectinids: king scallop (Pecten maximus), black
scallop (Mimachlamys varia), and queen scallop (Aequipecten opercularis). Studies
670
A. Ortega et al.