Biology, fishery and management of sardines (Sardinops sagax) in southern African waters

Sardines have been a major contributor to the pelagic fishery off southern Africa for several decades. The South African and Namibian stocks are separ ate, and seasonal hydrology, in conjunction with age-related behaviour, pro duces the observed size-distribution patterns. Sardines are relatively fast -growing and spawn repeatedly over the spring and summer months. Eggs and l arvae are transported from the Agulhas Bank to the west coast by the north- flowing jet current at the shelf edge. Sardines are omnivorous, microphagis t filter-feeders and are important prey for many piscivorous fishes, birds and mammals. There have been major fluctuations in sardine population bioma ss in southern Africa which have been associated with environment, regime s hifts, recruitment and fishing. South African and Namibian sardine catches peaked in the 1960s, declining dramatically thereafter, and the pelagic fis hing industry switched to anchovy. During the 1990s, sardine biomass increa sed but, although South African catches rose, the Namibian stock collapsed again. The annual South African total allowable catch is set through an ope rational management procedure that takes into account biomass estimates fro m comprehensive hydroacoustic surveys and the sardine by-catch in the ancho vy fishery.