Figure 4 shows the horizontal distribution of temperature recorded at 4 m depth by the thermograph. On the Tiger Bank the temperature was between 15 and 16 degrees, showing that upwelled water was still present. This can be traced up to Namibe. Further north the temperature in the surface layers varied between 21 and 26 degrees with a declining gradient towards the shore. Pockets of cold water were observed close to the shore at several locations. This indicated local limited upwelling along the coast. The areas of highest fish densities may be seen in connection with these phenomena.
The same pattern is reflected in the four hydrographical sections, Figures 5-6; a shoreward decline in temperature at surface and a slight rise in the sub-surface water masses towards the shore are indicated.
Four hydrographical sections were laid out close to the mouth of the Congo River, Figure 3. Figures 7a-d show the sections. In Figure 7a it is seen that the water masses from the river can be traced on the surface in most of the Cabinda region, while at 10 m depth the low salinity water was restricted to the river mouth (Figure 7d). A trial to trace isolines from samples at 5 m did not succeed as this was in the very mixing layer between the two water masses. It is seen that the main part of the river water was spread northwards into the Cabinda region.
