ecosystems through which they undertake long-distance migration. For these reasons marine megafauna are particularly vulnerable to non-natural mortality due to
fishing, and depleted populations may take decades to recover (Musick 1999).
Nevertheless, marine megafauna play a key role as apex predators in most ecosystems. Moreover, for social reasons, and within frameworks for the management and
conservation of natural environments, marine megafauna are considered flagship
(charismatic) species (Zacharias and Roff 2001; Albert et al. 2018). Thus, marine
megafauna capture public attention and raise conservationist concern for reasons
related to their role in marine biodiversity. Given the phenomenon of global climate
change, they also increase public awareness of the need to conserve marine species
or protect their future.
As mentioned, marine megafauna are mainly associated with pelagic ecosystems
and long-distance migrations. The Alboran Sea connects the Atlantic Ocean and
Mediterranean Sea and is thus a relevant hotspot for marine megafauna (Coll et al.
2010). In this area, the overlap between various human activities—such as marine
traffic or fisheries on the north and south coasts—and pollution has a strong negative
impact on their populations.
The areas of the Alboran Sea and the adjacent Strait of Gibraltar have been
included in various EU Directives and in different international agreements such as
the Barcelona Convention, the Convention of Migratory Species (CMS), the Bern
Convention, and CITES. The Alboran Sea is also a priority area according to the
Regional Activity Centre for Specially Protected Areas (RAC-SPA) established in
1985 by decision of the Contracting Parties to the Convention for the Protection of
the Mediterranean Sea Against Pollution (Barcelona Convention) within the framework of the Mediterranean Action Plan (MAP) of the United Nations Environment
Programme (UNEP).
21.2 Large Pelagic Sharks
Twenty-five shark species are included in the Shark Species Group of the International Commission for the Conservation of Atlantic Tunas (ICCAT). According to
their definition of pelagic, oceanic, and highly migratory sharks, just 12 species have
been reported in the Alboran Sea (https://www.mapama.gob.es/es/costas/temas/
proteccion-medio-marino/biodiversidad-marina/habitats-especies-marinos/default.
aspx). These species are included in the following families: Alopiidae
(Lamniformes), Carcharhinidae (Carcharhiniformes), Cetorhinidae (Lamniformes),
Lamnidae (Lamniformes), and Sphyrnidae (Carcharhiniformes). The most common
species are the blue shark (Prionace glauca), the shortfin mako (Isurus oxyrinchus),
and the thresher sharks (Alopias spp.).
Alopiidae (thresher sharks) are an easily identifiable family. They are characterized by the length of the upper lobe of the caudal fin, which is as long as the rest of
the body (Moreno et al. 1989). Of this family, the most common species in the
Alboran Sea is the common thresher (Alopias vulpinus). Moreno et al. (1989)
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J. C. Báez et al.
fishing, and depleted populations may take decades to recover (Musick 1999).
Nevertheless, marine megafauna play a key role as apex predators in most ecosystems. Moreover, for social reasons, and within frameworks for the management and
conservation of natural environments, marine megafauna are considered flagship
(charismatic) species (Zacharias and Roff 2001; Albert et al. 2018). Thus, marine
megafauna capture public attention and raise conservationist concern for reasons
related to their role in marine biodiversity. Given the phenomenon of global climate
change, they also increase public awareness of the need to conserve marine species
or protect their future.
As mentioned, marine megafauna are mainly associated with pelagic ecosystems
and long-distance migrations. The Alboran Sea connects the Atlantic Ocean and
Mediterranean Sea and is thus a relevant hotspot for marine megafauna (Coll et al.
2010). In this area, the overlap between various human activities—such as marine
traffic or fisheries on the north and south coasts—and pollution has a strong negative
impact on their populations.
The areas of the Alboran Sea and the adjacent Strait of Gibraltar have been
included in various EU Directives and in different international agreements such as
the Barcelona Convention, the Convention of Migratory Species (CMS), the Bern
Convention, and CITES. The Alboran Sea is also a priority area according to the
Regional Activity Centre for Specially Protected Areas (RAC-SPA) established in
1985 by decision of the Contracting Parties to the Convention for the Protection of
the Mediterranean Sea Against Pollution (Barcelona Convention) within the framework of the Mediterranean Action Plan (MAP) of the United Nations Environment
Programme (UNEP).
21.2 Large Pelagic Sharks
Twenty-five shark species are included in the Shark Species Group of the International Commission for the Conservation of Atlantic Tunas (ICCAT). According to
their definition of pelagic, oceanic, and highly migratory sharks, just 12 species have
been reported in the Alboran Sea (https://www.mapama.gob.es/es/costas/temas/
proteccion-medio-marino/biodiversidad-marina/habitats-especies-marinos/default.
aspx). These species are included in the following families: Alopiidae
(Lamniformes), Carcharhinidae (Carcharhiniformes), Cetorhinidae (Lamniformes),
Lamnidae (Lamniformes), and Sphyrnidae (Carcharhiniformes). The most common
species are the blue shark (Prionace glauca), the shortfin mako (Isurus oxyrinchus),
and the thresher sharks (Alopias spp.).
Alopiidae (thresher sharks) are an easily identifiable family. They are characterized by the length of the upper lobe of the caudal fin, which is as long as the rest of
the body (Moreno et al. 1989). Of this family, the most common species in the
Alboran Sea is the common thresher (Alopias vulpinus). Moreno et al. (1989)
708
J. C. Báez et al.