p. 177 - 203 COMPOSITION AND STRUCTURE OF FISH COMMUNITIES IN COASTAL WATERS OF NORTHERN AND NORTH EASTERN SOMALIA G. I. Muller and V. Dumitrescu Romanian Marine Research Institute Constanta Abstract Fisheries investigations carried out during November 1983-April 1984 both along the northern (Gulf of Aden) and north-eastern (Indian Ocean) coasts of Somalia allowed sampling and identification of 236 species of fishes. According to physical conditions encountered there are important differences in composition of fish communities within the neritic zone. Inside the Gulf of Aden, above steep and very rough bottoms of the narrow shelf, the black triggerfish (Odonus niger)was the throughout dominating species (66.5%) in catches, while south of Ras Asir-above the broad and evently patterned shelf-pelagic species of the genera Sardinella, Decapterus, Etrumeus and Scomber were the main dominance. Observations on coral reef dwelling were also performed near Berbera.