In the northern region of CECAF, numerous resource surveys and scientific expeditions have been carried out. In Tables 66–73 the cruises of research and fishing vessels are summarized (after van der Knaap, 1985). During the surveys, pelagic and/or bottom trawl hauls were taken. The main objective of the resource surveys was the evaluation of the biomass. Unfortunately, no sparid biomass estimates were made, although for several surveys, yields per hour and the percentage in total catch are known.
