Benguela - Pta Palmeirinhas
Figure 3 shows the distribution of surface temperature observed with the thermograph at 4 m of depth and the distribution of temperature, salinity and oxygen in the profiles. The surface temperature distribution is characterized by an increase oceanwards, from about 25°C close to the shore increasing to 28°C off the shelf. In the two sections worked in the region there is a strong thermocline well demonstrated at 25-50 m depth followed by a gradual decrease of temperature towards deeper layers. A characteristic of the sections is the low salinity content of the surface waters, advected from the Congo river runoff by the southward flowing Angola current. The oxygen content over the shelf is relatively high, presenting values which are not likely to limit the distribution of fish on the shelf.
Pta. Palmeirinhas - Cabinda
Figure 4 shows the distribution of surface temperature observed with the thermograph at 4 m depth and the distribution of temperature, salinity and oxygen in the profiles. The surface temperature at the Pta da Moita Seca are about the same from the coast on to the slope area. The temperature decrease gradually with increasing depth and a thermocline is not developed. A strong halocline is developed at 10 m and the salinity is increasing offshore. The lower salinity close to the coast could indicate influence of the Congo River. The temperature profile at Cabinda is similar to the previously mentioned profile and a themocline is not developed. The influence of the River Congo is demonstrated in the low salinity water at surface over the hole section and a strong halocline is shown at about 10 m. In the horizontal temperature chart a core of water with 25°C is observed all along the coast and the temperature increase to 27°C off the shelf.
The hydrografic profiles and current observation during trawling and steaming indicate that the dominating direction of the water movements are north to west. The southward flowing Angola current is not detected in the surveyed area.
The oxygen content over the shelf is relatively high and the values are not likely to limit the distribution of fish.
