The Alboran Sea is the westernmost portion of the

Mediterranean Sea The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

, lying between the

Iberian Peninsula The Iberian Peninsula ( ), also known as Iberia, is a peninsula in south-western Europe. Mostly separated from the rest of the European landmass by the Pyrenees, it includes the territories of peninsular Spain and Continental Portugal, comprisin ...

and the north of

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

(Spain on the north and

Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...

and

Algeria Algeria, officially the People's Democratic Republic of Algeria, is a country in the Maghreb region of North Africa. It is bordered to Algeria–Tunisia border, the northeast by Tunisia; to Algeria–Libya border, the east by Libya; to Alger ...

on the south). The

Strait of Gibraltar The Strait of Gibraltar is a narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Europe from Africa. The two continents are separated by 7.7 nautical miles (14.2 kilometers, 8.9 miles) at its narrowest point. Fe ...

, which lies at the west end of the Alboran Sea, connects the Mediterranean with the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

Geography

Its average depth is and maximum depth is . The

International Hydrographic Organization The International Hydrographic Organization (IHO) (French: ''Organisation Hydrographique Internationale'') is an intergovernmental organization representing hydrography. the IHO comprised 102 member states. A principal aim of the IHO is to ...

defines the limits of the Alboran Sea as follows:

''On the West.'' The Eastern limit of the Strait of Gibraltar: A line joining from tip ( Europa Point) of '' Cap Gibraltar'' in Europe () to the tip of the '' Península de Almina'' of
Ceuta Ceuta (, , ; ) is an Autonomous communities of Spain#Autonomous cities, autonomous city of Spain on the North African coast. Bordered by Morocco, it lies along the boundary between the Mediterranean Sea and the Atlantic Ocean. Ceuta is one of th ...
in Africa (). ''On the East.'' A line joining from '' Cabo de Gata'' in
Andalusia Andalusia ( , ; , ) is the southernmost autonomous communities of Spain, autonomous community in Peninsular Spain, located in the south of the Iberian Peninsula, in southwestern Europe. It is the most populous and the second-largest autonomou ...
in Europe () to ''Cap Fegalo'', near Oran, Algeria in Africa ().

Several small islands dot the sea, including the eponymous Isla de Alborán. Most, even those close to the African shore, belong to Spain.

Geology

The Alboran domain, the seafloor beneath the Alboran Sea (known as the internal zones) together with the surrounding mountains (known as the external zones; the Gibraltar Arc and

Atlas Mountains The Atlas Mountains are a mountain range in the Maghreb in North Africa. They separate the Sahara Desert from the Mediterranean Sea and the Atlantic Ocean; the name "Atlantic" is derived from the mountain range, which stretches around through M ...

), is mostly made of

continental crust Continental crust is the layer of igneous, metamorphic, and sedimentary rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as '' continental shelves''. This layer is sometimes called '' si ...

and marks the westernmost terminus of the

terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or " sutured" to crust lying on another plate. The crustal block or fragment preserves its d ...

s that were subducted between the African and Eurasian Plates when the

Tethys Ocean The Tethys Ocean ( ; ), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean during much of the Mesozoic Era and early-mid Cenozoic Era. It was the predecessor to the modern Indian Ocean, the Mediterranean Sea, and the Eurasia ...

closed. Reoccurring earthquakes at a depth of about indicate that this

subduction Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

is ongoing and that complex interactions between the

lithosphere A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time ...

and mantle are forming the region. The internal zones are made of Late Paleozoic to

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

rocks that were piled up during the Tertiary and has been extended since the Early

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

. The seafloor is morphologically complex with several sub-basins, including three main sub-basins named West, East, and South Alboran Basins, ridges, and seamounts. The most prominent structure in the Alboran Sea is the Alboran Ridge which stretches southwest from the volcanic Alborán Island.

Oceanography

Surface currents in the Alboran Sea, influenced by the prevailing winds, flow eastward, bringing water from the Atlantic into the Mediterranean; deeper subsurface currents flow westward, carrying saltier Mediterranean water over the Gibraltar sill into the Atlantic. Thus there is typically a vertical rotary circulation, also known as a gyre, in the Alboran Sea as a result of this exchange of water.

Ecology

The Alboran Sea is a transition zone between ocean and sea, containing a mix of Mediterranean and Atlantic species. The Alboran Sea is habitat for the largest population of

bottlenose dolphin The bottlenose dolphin is a toothed whale in the genus ''Tursiops''. They are common, cosmopolitan members of the family Delphinidae, the family of oceanic dolphins. Molecular studies show the genus contains three species: the common bot ...

s and the last population of

harbour porpoise The harbour porpoise (''Phocoena phocoena'') is one of eight extant species of porpoise. It is one of the smallest species of cetacean. As its name implies, it stays close to coastal areas or river estuaries, and as such, is the most familiar ...

s in the western Mediterranean, and is the most important feeding grounds for

loggerhead sea turtle The loggerhead sea turtle (''Caretta caretta'') is a species of sea turtle, oceanic turtle distributed throughout the world. It is a marine reptile, belonging to the Family (biology), family Cheloniidae. The average loggerhead measures around ...

s in Europe. The Alboran sea also hosts important

commercial fisheries Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often p ...

, including

sardine Sardine and pilchard are common names for various species of small, oily forage fish in the herring suborder Clupeoidei. The term "sardine" was first used in English during the early 15th century; a somewhat dubious etymology says it com ...

s and

swordfish The swordfish (''Xiphias gladius''), also known as the broadbill in some countries, are large, highly migratory predatory fish characterized by a long, flat, pointed bill. They are the sole member of the Family (biology), family Xiphiidae. They ...

. In 2003, the

World Wildlife Fund The World Wide Fund for Nature (WWF) is a Swiss-based international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the ...

raised concerns about the widespread drift net fishing endangering populations of dolphins, turtles, as well as other marine animals. In 2023, the European Union, Morocco, and Algeria agreed to ban bottom fishing practices around Cabliers Bank, protecting the only cold-water coral reef known to be growing in the Mediterranean. An arc of mountains, known as the Gibraltar Arc, wraps around the northern, western and southern sides of the Alboran Sea. The Gibraltar Arc is made up of the

Baetic Cordillera The Baetic System or Betic System () is one of the main systems of mountain ranges in Spain. Located in the southern and eastern Iberian Peninsula, it is also known as the Cordilleras Béticas (Baetic Mountain Ranges) or Baetic Mountains. The n ...

of Southern Spain and the

Rif Mountains The Rif (, ), also called Rif Mountains, is a geographic region in northern Morocco. It is bordered on the north by the Mediterranean Sea and Spain and on the west by the Atlantic Ocean, and is the homeland of the Rifians and the Jebala people. ...

of Morocco. These mountains, known to ecologists as the Baetic-Rifan complex, comprise one of the Mediterranean's

biodiversity hotspot A biodiversity hotspot is a ecoregion, biogeographic region with significant levels of biodiversity that is threatened by human habitation. Norman Myers wrote about the concept in two articles in ''The Environmentalist'' in 1988 and 1990, after ...

s; like the Alboran Sea, the Baetic-Rifan complex represents a transition between the Mediterranean and Atlantic (

Macaronesia Macaronesia (; ) is a collection of four volcanic archipelagos in the Atlantic Ocean#North Atlantic, North Atlantic Ocean, off the coast of North Africa and Europe. Each archipelago is made up of a number of list of islands in the Atlantic Oc ...

n) ecological zones. The moderating influence of the Atlantic has allowed many

relict A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...

species in the Baetic and Rif mountains to survive the climatic fluctuations of the last few million years that have caused them to become extinct elsewhere around the Mediterranean basin.

Islands

There are some small islands in the sea: * Isla de Alborán * Islas Chafarinas * Peñón de Alhucemas *

Peñón de Vélez de la Gomera () also known as Hajar Badis () is a Spanish exclave and rocky tidal island in the western Mediterranean Sea connected to the Moroccan shore by a sandy isthmus. It is also connected to a smaller islet to the east, La Isleta, by a rocky isthm ...

References

Notes

Sources

* * * {{List of African seas Marginal seas of the Mediterranean Seas of Spain Bodies of water of Morocco Bodies of water of Algeria Morocco–Spain border Gibraltar–Spain border Algeria–Morocco border European seas Seas of Africa Back-arc basins