BIOMASS SPECTRA IN BENTHIC FISH ASSEMBLAGES IN THE BENGUELA SYSTEM

Biomass spectra in the different benthic fish assemblages at depths be tween 100 and 800 m off the coast of Namibia were studied over a perio d of 3 yr. These assemblages were located in areas spanning active upw elling centres on the shelf and zones of lower productivity on the low er slope. The slopes of the curves for the normalized size distributio ns were related to zonal productivity and abundance of the smallest si ze classes. In the main upwelling centre, in which abundance of small specimens was higher and community diversity lower, biomass clearly dr opped off with increasing size; teleost fishes and mid-level predators (which prey on euphausiids and other pelagic crustaceans) predominate d. In the less productive zone, where the biomass of small specimens w as very low and community diversity very high, biomass increased or at least tended to remain constant with size and elasmobranchs and apex predators (which prey on fish and cephalopods) were most abundant.