The Red Sea has been a region of natural history exploration by European scientists for more than 200 years. Previous to the completion of the Suez Canal in 1869, travellers generally started their journeys of exploration from one of two points. From the east coast of Egypt (usually Suez), they could travel by vessels to the Arabian coast and then on to the Ethiopian coast, or they entered the Red Sea from the south, through the Strait of Bab el Mandeb, coming by ship via the Cape of Good Hope. After the completion of the Suez Canal many expeditions passed through the Red Sea on their way to other parts of the Indian Ocean. During that time numerous marine algae were collected, resulting in the description of many species with the Red Sea as type locality. Ahistorical review of phycological research in the Red Sea is given by PAPENFUSS (1968). The first record of marine algae from the Red Sea dates back to 1756, and since then there have been a number of important contributors to the knowledge of the marine algae of the Red Sea. These include Forsskål (18th century); Turner, Delile, Lamouroux, Decaisne, Agardh, Montagne, De Notaris, Zanardini, Piccone, Hauck, and Bornet (19th century); Reinbold, Lyle, Christensen, Børgesen, Nasr, Newton, Rayss, and Dor (20th century). Amilestone in macroalgal research in the Red Sea was the catalogue and bibliography of the Red Sea benthic algae, compiled by PAPENFUSS (1968). Recent studies include WALKER (1987) and ATEWEBERMAN (1997). PRICE et al. (1988) studied the ecology of seagrasses in the Red Sea. Global taxonomic and biogeographical studies on seagrasses have been carried out by DEN HARTOG (1970) and PHILLIPS& MEÑEZ (1988). Very little is known about the seaweeds and seagrasses of the Gulf of Aden. ORMOND and BANAIMOON (1994) investigated the ecology of intertidal macroalgal assemblages on the Hadramaut coast of southern Yemen. This study resulted in a list of 163 taxa of seaweeds. WYNNE and JUPP (1998) compiled 74 new records of benthic marine algae for the flora of Oman. More recently, the United Nations Development Programme (UNDP) has become involved in the conservation and sustainable use of the biodiversity of the Socotra Archipelago (UNDP/GEF Project YEM/96/G32). The seaweeds and seagrasses of these islands have been studied by LELIAERT (1999), SCHILS (2000), WYNNE & LELIAERT (2000), SCHILS (2002), SCHILS & COPPEJANS (2002, 2003a, 2003b), SCHILS et al. (2003a, 2003b). The seaweeds and seagrasses of the north coast of Somalia remain largely unstudied.