Alborán Deep IMMA

Area Size

22 660 km2

Qualifying Species and Criteria

Sperm whale – Physeter macrocephalus

Criterion A; C (2)

Cuvier’s beaked whale – Ziphius cavirostris

Criterion A; B (2); C (1)

Risso’s dolphin – Grampus griseus

Criterion B (2); C (1, 2)

Long-finned pilot whale – Globicephala melas

Criterion B (2); C (1, 2)

Marine Mammal Diversity 

Criterion D (2)

Balaenoptera physalus, Delphinus delphis, Tursiops truncatus

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The Alborán Deep is characterised by a complex bottom topography with many escarpments, ridges, canyons, and seamounts, all creating a good habitat for squid-eating deep-diving species in the Alborán Sea. Concentrated in this area have been numerous sightings of long-finned pilot whales (Globicephala melas), Risso’s dolphins (Grampus griseus), Endangered Mediterranean sperm whales (Physeter macrocephalus), and Vulnerable Cuvier’s beaked whales (Ziphius cavirostris), all confirmed from spatial modelling of their habitats. This area has the highest density in the Mediterranean for pilot whales, and one of the three highest densities for beaked whales.

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

Mediterranean subpopulation of sperm whales is considered to be Endangered by the IUCN Red List of Threatened Species. The Alborán Sea forms a gateway between the Mediterranean Sea and the Atlantic Ocean, and therefore forms a passage area for animals that might travel between both areas. It is especially important as a connection area between the Strait of Gibraltar and the rest of the Mediterranean; there is photo-id evidence of recaptures of animals in the Strait of Gibraltar, the Alborán Sea and the Ligurian Sea. The subpopulation of Cuvier’s beaked whale in the Mediterranean Sea is listed as Vulnerable (VU) C2a(ii) IUCN Red List of Threatened Species, with a decreasing population trend (Cañadas and Notarbartolo di Sciara, 2018).

Criterion B: Distribution and Abundance

Sub-criterion B2: Aggregations

Long-finned pilot whale density within the area is the highest recorded within the Mediterranean. Large aggregations of long-finned pilot whales have been observed every year in all seasons with mean group size of 29 and up to 350. The latest abundance estimate for long-finned pilot whales is of 7,440 individuals. Satellite tagging of pilot whales also shows an intense use of the area.

Cuvier’s beaked whale densities within the area are some of of the highest recorded for each of the species within the Mediterranean. Cuvier’s beaked whales are found every season and this area shows one of the highest densities of this species in the Mediterranean as shown by the Mediterranean wide density surface modelling of Cuvier’s beaked whales, with an estimate of 429 individuals in the Alborán Sea.

Risso’s dolphin densities within the area are some of of the highest recorded for each of the species within the Mediterranean. Risso’s dolphins, although encountered much less often than pilot whales, are also sighted every year and show high number of identified individuals with photo-identification, when compared with other areas such as the Ligurian Sea. The most recent abundance estimate for Risso’s dolphins is of 864 animals only in the northern third of the Alborán Sea with an extension to include the Alborán Island.

Criterion C: Key Life Cycle Activities

Sub-criterion C1: Reproductive Areas

Calves are observed very frequently for long-finned pilot whales and Risso’s dolphins, indicating that this is a reproductive area for them. Calves have also been observed in Cuvier’s beaked whales. The presence and number of calves has been recorded during long term monitoring efforts in the region. For every encounter of cetaceans, 64% of the encounters of pilot whales and 32% of the Risso’s dolphin encounters included calves in the groups. Mating behaviour was directly observed in many occasions in pilot whale’s groups. Calves have been observed in Cuvier’s beaked whales although much less frequently than for the other two species.

Sub-criterion C2: Feeding Areas

Feeding behaviour has been observed in the four deep diver species in this area: sperm whales, long-finned pilot whales, Cuvier’s beaked whales and Risso’s dolphins. Data has been gathered in this area from 1992 to 2011 (20 years), in all seasons but mainly in Summer. Indirect evidence during many observations (long dives) have been observed frequently in the four deep diver species in this area, which is rich in cephalopods due to the bathymetric characteristics of the area. Pilot whales were tagged with DTAGs in 2010 and 2011 in the Alborán Sea showing typical forging/feeding behaviour during long dives. Cuvier’s beaked whales were followed over long periods of time (several hours each) collecting data on diving behaviour through focal follow, showing typical behaviour of long dives for foraging/feeding. Long dives, typical for foraging/feeding have also been observed in sperm whales and Risso’s’ dolphins.

Criterion D: Special Attributes  

Sub-criterion D2: Diversity

This is an area with diversity of deep diver species (sperm whales, long-finned pilot whales, Cuvier’s beaked whales and Risso’s dolphins), but also holds large aggregations of other cetacean species (striped, common, and common bottlenose dolphins), and regular (although with less density) presence of migrating fin whales. Other species have been observed sporadically (false killer whale, killer whale, minke whale) making it the area with the highest cetacean diversity in the Mediterranean.

Supporting Information

Cañadas, A. and Sagarminaga, R. 2002. Identificación de las áreas de especial interés para la conservación de los cetáceos en el Mediterráneo español. Report available from (Cañadas, A.).

Cañadas, A. and Hammond, P.S. 2006. Model-based abundance estimates for bottlenose dolphins off southern Spain: implications for conservation and management. Journal of Cetacean Research and Management 18(1): 13-27.

Cañadas, A. 2006. Towards conservation of dolphins in the Alboran Sea. PhD Thesis. Universidad Autonoma de Madrid.

Cañadas, A. and Sagarminaga, R. 2000. The northeastern Alboran Sea, an important breeding and feeding ground for the long-finned pilot whale (Globicephala melas) in the Mediterranean Sea. Marine Mammal Science 16(3): 513-529.


Cañadas, A. Sagarminaga, R., Marcos, P. y Urquiola, E. 2004. Sector Sur (Andalucía y Ceuta). In: Proyecto Mediterráneo. Zonas de especial interés para la conservación de los cetáceos en el Mediterráneo español (Ed. J.A. Raga and J. Pantoja), pp. 133-190. Minsterio de Medio Ambiente. Organismo Autónomo Parques Nacionales. Madrid.

Cañadas, A., Hammond, P.S. 2008. Abundance and habitat preferences of the short-beaked common dolphin Delphinus delphis in the southwestern Mediterranean:Implications for conservation.Endangered Species Research,4,3,309,331

Cañadas, A., Sagarminaga, R., de Stephanis, R., Urquiola, E., Hammond, P.S., 2005. Habitat preference modelling as a conservation tool: proposal of marine protected areas for cetaceans in Southern Spain. Aquat. Conserv. 15, 495-521.

Cañadas, A., Sagarminaga, R., García-Tiscar, S., 2002. Cetacean distribution related with depth and slope in the Mediterranean waters off southern Spain. Deep Sea Res. I, 49(11), 2053-2073.

Cañadas, A., Vázquez, J.A., 2014. Conserving Cuvier’s beaked whales in the Alborán Sea (SW Mediterranean): Identification of high density areas to be avoided by intense man-made sound. Biol. Conserv. 178, 155-162.

Cañadas, A. and Notarbartolo di Sciara, G. 2018. Ziphius cavirostris Mediterranean subpopulation. The IUCN Red List of Threatened Species 2018: e.T16381144A50286386. Downloaded on 29 January 2019.

Carpinelli, E., Gauffier, P., Verborgh, P., Airoldi, S., David, L., Di-Méglio, N., Cañadas, A., Frantzis, A., Rendell, L., Lewis, T., Mussi, B., Pace, D.S., de Stephanis. R. 2014. Assessing sperm whale (Physeter macrocephalus) movements within the Mediterranean Sea through photo-identification, Aquatic Conservation: Marine and Freshwater Ecosystems (special issue) 24, Suppl (1): 23-30

Cheney, R.E. y Doblar, R.A. 1979. Alboran Sea 1977: Physical Characteristics and Atmospherically induced variations of the Oceanic Frontal System. Tactical Analysis Division. U.S. Naval Oceanographic Office. Technical Note 3700-82-79.

INDEMARES Report. 2010. Available from Fundacion Biodiversidad, Spain.
Parrilla, G. y Kinder, T.H., 1987. Oceanografía física del mar de Alborán. Boletín del Instituto Español de Oceanografía, 4(1): 133-165.

Rodriguez, J., 1982. Oceanografía del Mar Mediterráneo. Ed. Pirámide. 174 p.
Rubín, J.P., Gil, J., Ruiz, J., Cortés, M.D., Jiménez-Gómez, F., Parada, M. and Rodriguez, J. (1992). La distribución ictioplanctónica y su relación con parámetros físicos, químicos y biológicos en el sector norte del Mar de Alboran, en julio de, 1991 (Resultados de la Campaña “Ictio.Alboran 0791”). Informe Técnico del Instituto Español de Oceanografía, 139. Madrid.

Tyack, P. 2012. Tagging and Playback Studies to Toothed Whales. Report of ONR Award Number N000140910528.

Verborgh, P., Gauffier, P., Esteban, R., Giménez, J., Cañadas, A., Salazar J.M., de Stephanis, R. 2016.Conservation Status of Long-Finned Pilot Whales, Globicephala Melas, in the Mediterranean Sea

Wierucka, K., Verborgh, P., Meade, R., Colmant, L., Gauffier, P., Esteban, R., de Stephanis, R. and Cañadas, A. 2014. Differences in survival rates and the effect of the Morbillivirus epizootic between clusters of long-finned pilot whales (Globicephala melas) in the Mediterranean Spanish waters. Marine Ecology Progress Series, 502:1-10.


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