The round herring Etrumeus whiteheadi, an abundant, underexploited clupeoid species off the coast of southern Africa

Abstract

The round herring Etrumeus whiteheadi occurs over the continental shelf between southern Namibia and the east coast of southern Africa. Its estimated biomass during the late 1980s was at least one million tons, making it one of the most abundant yet least exploited fish populations of the region. A synthesis of recent findings on abundance, population structure, size-related distribution patterns and fish behaviour is provided, drawing on the results of 18 acoustic and bottom-trawl surveys carried out between 1983 and 1989. Spawning takes place in deep water over the shelf and shelf-slope during the austral winter and spring. Juveniles aggregate inshore, where they school together with juvenile anchovy Engraulis capensis and other pelagic species. Juvenile round herring on the West Coast migrate southwards and, as they grow, gradually occupy deeper water and perform diel vertical migrations. The diet and distribution of round herring overlap extensively with those of the commercially important anchovy and pilchard Sardinops ocellatus populations. Biological interactions with those species and the technical interactions that affect the commercial purse-seine fishery are reviewed.