The positions of the hydrographical sections are shown in Figure 1-2. Figures 3-4 show the distribution of temperature, salinity and oxygen in each section. The surface temperature varied between 20 Ñ and 28 Ñ with the lowest temperatures at Baia dos Tigres and the highest off Lobito. The thermocline for all the hydrographical sections lies between 15 and 40 m. The sharpest thermoclines were observed off Lobito and Ponta da Moita Seca. In the other areas the thermocline decreased more gradually with depth. As shown in the figures, the oxygen content decreases rapidly in the surface layers. However values below 1 ml/1 are found only beyond the continental shelf. To study the freshwater flow from the Congo river special hydrographical stations were occupied. In Figures 5 and á the distribution of temperature and salinity is shown at the surface and at 5 m depth. The northward flow of freshwater reduces salinity in the upper 5 meters up to 50 nm north of the river mouth whereas no such reduction was found at 10 m depth. The temperature at the surface and at 5 and 10 m depth decreases north of the river and is some 2-3 Ñ lower than just south of the river. At the surface and at 5 m depth the temperature at the mouth of the river was higher than just outside the rivermouth, but at 10 m depth the temperature was 3-4 Ñ lower than just outside the rivermouth.
