Schools of Sardinella aurita in midwater and close to the bottom. Echo recording at fishing station TP 261 off Gabon, S 2°20'. Day situation. Bottom not suitable for trawling. (Depth interval: 20 m.)
Schools of Sardinella aurita in midwater and close to the bottom. Echo recording at fishing station TP 261 off Gabon, S 2°20'. Day situation. Bottom not suitable for trawling. (Depth interval: 20 m.)
The diagrams are representative of a frequently occurring feature with dense plankton layers screening the scattered fish registrations. The situation makes the estimation of fish density most difficult.
Transverse section near fishing station TP 243 off Congo, S 5° 15'. Night situation. Myctophid and plankton layer off the shelf and scattered pelagic fish, probably Sardine 11 a over the plateau. Bottom trawlable, but without fish registrations. (Depth interval: 20 m.)
Day registration near fishing ststion TP 247, S 1° 42'. Example of fish (Sardinella aurita) and plankton occurring separately, making assessment of fish density relatively easy.
