The Alboran Sea is the western portion of the Mediterranean Sea, lies between Spain on the north and Morocco and Algeria on the south. The Strait of Gibraltar lies at the west end of the Alboran Sea connects the Mediterranean with the Atlantic Ocean. The sea's average depth is 1,461 feet (445 m) and maximum depth is 4,920 feet (1,500 m).
Alboran Sea flows eastward at the surface and brings water from the Atlantic into Mediterranean; but deeper subsurface water flows westward carrying saltier Mediterranean water into the Atlantic. In the Alboran Sea, as a result of this exchange of water there is a rotary circulation, it is also known as a gyre. The Alboran Sea is a transition zone between the two seas, it contains a mix of Mediterranean and Atlantic species.
The Alboran Sea is the home for the largest population of bottlenose dolphins in the western Mediterranean, is habitat to the last population of harbour porpoises in the Mediterranean. It is the most significant feeding grounds for loggerhead sea turtles in Europe. The Alboran Sea also hosts significant profitable fisheries, including sardines and swordfish.
There are several small islands in the sea, such as Isla de Alboran.