The strait of Bab al-Mandeb, “the gate of tears” or “the gate of the wailing yard”, joins the high seas of the Gulf of Aden and the Indian Ocean to those of the Red Sea. The name is primarily used by geographers to designate the narrowest part of the passage, between Ras Bab al-Mandeb on the Asian shore and Ras Siyan in Africa. At this point it is bordered on the east by the Yemen Arab Republic (Northern Yemen) and the People's Democratic Republic of Yemen (Southern Yemen), and in the west by the Republic of Djibouti (formerly the French Territory of the Afars and Issas). About 14 miles farther north, where the Red Sea (or, for that matter, the strait) is nearly 20 miles wide, lies the coast of Ethiopia (the province of Eritrea). All the riparians claim a territorial sea of 12 miles, and the Yemen Arab Republic, as well as the People's Democratic Republic of Yemen, also claim jurisdiction for certain purposes in an additional zone of 6 miles.On the eastern shore of the strait of Bab al-Mandeb lies the peninsula of Ras Bab al-Mandeb, which is about 6–10 km. wide. It consists of rocky, volcanic plains with several hills of 200–300 m. The coast of Ras Bab al-Mandeb is surrounded by coral reefs of a width of up to 1500 m. The border between North Yemen and South Yemen passes down the middle of Ras Bab al-Mandeb.
Factors influencing microbial mat composition, distribution and dinitrogen fixation in three western Indian Ocean coral reefs