Figure 4 illustrates the distribution of fish as observed with the acoustic integration system. The units of acoustic reflection is 0.1 × m2/nm2 reflecting surface. An arbitrary scale has been used to illustrate different levels of concentration. The acoustic data will later be used for biomass estimates.
GABON
The areas of aggregations of pelagic fish are as shown by Figure 4 few and small. Those found along the edge of the shelf from off Sette Cama to Cap Lopez should be ascribed to small sized horse mackerel Trachurus trecae and partly Spanish mackerel Scomber japonicus. The small patch of higher density inshore near the border to Congo represents an area of schooling Clupeids, probably Sardinella maderensis. Demersal fish consisting mostly of small sized Sparids were recorded over larger areas, but with low den-sides only. A very similar picture of low densities of fish in mid water was obtained in the survey in March 1985.
CONGO
Some pelagic fish was recorded in a narrow band along the Congo coast, mostly at depths between 20 and 30 m. The highest densities were found in the northern part where some schools probably of sardinella were observed. Otherwise samples in this area indicated that the recordings derived from West African ilisha, Ilisha africana, bumper Chloroscombrus chrysurus and some barracuda Sphyraena guachancho. Only insignificant recordings of demersal fish were made in Congo waters in this survey.
