Top predators in the Benguela ecosystem — implications of their trophic position

摘要: Many top predators in the Benguela ecosystem feed on prey species targeted by commercial fisheries. Their roles as indicators of state exploited resources, competitors with fisheries for and susceptible to impact from fishing those resources are briefly considered. Trends occurrence anchovy Engraulis capensis pilchard Sardinops ocellatus diet Cape gannets Morus off South Africa's west coast related significantly survey estimates abundance these fish species, they provide useful confirmation estimates. In 1980s, decreased gannets, but increased. both northern southern portions system, groundfish were thought eat most (66–73%) total quantity cephalopods vertebrates consumed man 1980s. African fur seals Arctocephalus pusillus pusillus, predatory pelagic removed roughl...