ABSTRACT: Biomass spectra in the different benthic fish assemblages at depths between 100 and 800 m off the coast of Namibia were studied over a period of 3 yr. These assemblages were located in areas spanning active upwelling centres on the shelf and zones of lower productivity on the lower slope. The slopes of the curves for the normalized size distributions were related to zonal productivity and abundance of the smallest size classes. In the main upwelling centre, in which abundance of small specimens was higher and community diversity lower, biomass clearly dropped off with increasing size; teleost fishes and mid-level predators (which prey on euphausiids and other pelagic crustaceans) predominated. In the less productive zone, where the biomass of small specimens was 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.

KEY WORDS: Biomass spectra . Fish . Benguela system . SE Atlantic

Published in MEPS Vol. 138 (1996) on July 25
ISSN: 0171-8630. Copyright © Inter-Research, Oldendorf/Luhe, 1996