Gulf of Aden

Lore & Background

In antiquity, the Gulf of Aden was a thriving area of international trade connecting Ptolemaic Egypt and Rome with Classical India, its Indonesian colonies, and Han China. The 1st-century *Periplus of the Erythraean Sea*, a Greek navigational text, documents this era. The gulf is a deepwater body of the Indian Ocean, bordered by Yemen to the north, Djibouti to the west, and the Guardafui Channel, Socotra Archipelago, and Puntland/Somaliland to the south. It connects to the Red Sea via the Bab-el-Mandeb strait and narrows westward into the Gulf of Tadjoura. The Aden Ridge runs along its center, with tectonic activity widening the gulf by about 15 mm annually. Water temperatures range from 15 to 28 °C depending on season and monsoons; salinity at 10 meters depth varies from 35.3‰ off the Somali coast to 37.3‰ in the central gulf, with oxygen content typically between 4.0 and 5.0 mg/L. The gulf is part of the vital Suez Canal shipping route, with 21,000 ships crossing yearly, many carrying Persian Gulf oil. Key cities include Aden, Mukalla, and Bosaso. Despite limited large-scale commercial fishing, the coastline supports many isolated fishing towns, with sardines, tuna, kingfish, mackerel, crayfish, and sharks caught locally. The gulf hosts unique biodiversity including fish, coral, seabirds, and invertebrates, though whales, dolphins, and dugongs were severely reduced by commercial and illegal hunts in the 1960s–1970s. The critically endangered Arabian humpback whale was once common but now only a few large whales, such as Bryde's whales, remain.

Reader's Guide

The Gulf of Aden is a critical maritime corridor, with approximately 11% of the world's seaborne petroleum passing through it on its way to the Suez Canal or to regional refineries. India receives US$50 billion in imports and sends US$60 billion in exports through this area annually, and to protect its trade, India keeps a warship escort in the area. The gulf's coastline supports many isolated fishing towns and villages, and it is richly supplied with fish, turtles, lobsters, crayfish, and sharks. Despite a lack of large-scale commercial fishing facilities, local fishing takes place close to the shore, with sardines, tuna, kingfish, and mackerel making up the bulk of annual catches. The gulf has a unique biodiversity that includes many varieties of fish, coral, seabirds, and invertebrates, benefiting from a relative lack of pollution in the past. However, environmental groups fear that the lack of a coordinated effort to control pollution may jeopardize the gulf's ecosphere. Whales, dolphins, and dugongs were once common before being severely reduced by commercial hunts, including mass illegal hunts by the Soviet Union and Japan in the 1960s and 1970s. The now critically endangered Arabian humpback whales were once seen here in large numbers, but only a few large whales still appear in the gulf waters.

Did You Know?

• The Gulf of Aden is widening by about 15 mm (0.59 in) per year due to tectonic activity at the Aden Ridge.
• In medieval times, the gulf was called the Gulf of Berbera, reflecting the importance of the port of Berbera in regional and international trade.
• The gulf's salinity at 10 meters depth varies from 35.3‰ along the eastern Somali coast to as high as 37.3‰ in its centre.
• The 1st-century Periplus of the Erythraean Sea is a Greek navigational text of unknown authorship that documents the era of direct trade with India.