THE MICROCOPEPOD FAUNA IN THE EASTERN MEDITERRANEAN AND ARABIAN SEA - A COMPARISON WITH THE RED-SEA FAUNA

Multiple opening-closing nets of 0.05 mm mesh size were employed to study the community structure and vertical distribution of microcopepods at selected stations in the Red Sea, Arabian Sea and Eastern Mediterranean Sea down to a maximum depth of 185 m. Calanoids, cyclopoids (Oithona and Paroithona) and poecilostomatoids (mainly Oncaea) were the 3 most abundant orders. In the epipelagic zone (0-100 m), these orders occurred at similar abundance levels, whereas in the meso- and bathypelagic zones the poecilostomatoid genus Oncaea dominated numerically by about 60-80% of all copepodids. The species diversity of Oncaea in the Red Sea is compared with preliminary results from the two adjacent regions. In the deep Eastern Mediterranean Sea, the number of species appears to be similar to that in the deep Red Sea and low as compared to the deep Arabian Sea. In this latter area an extremely speciose Oncaea fauna was found at depth below the oxygen-minimum-zone (900-1850 m). The results are related to the differences in the hydrographic conditions of these 3 areas.