The 1980s – a decade of change in the Benguela ecosystem

Abstract

Changes that occurred in sea surface and some deeper temperatures, surface winds, currents, plankton and some dominant crustacean (rock lobster Jasus lalandii), molluscan (squid Loligo vulgaris reynaudii and abalone Haliotis midae), fish (anchovy Engraulis capensis, pilchard Sardinops ocellatus, Cape hakes Merluccius spp., sole Austroglossus pectoralis, kingklip Genypterus capensis and various species of linefish) and seabird (Cape gannet Morus capensis) resources in the Benguela ecosystem in the 1980s are documented. Although fishing had a clear influence on changes in some of the resources, a wide spectrum of organisms, from plankton to top predators, were influenced directly or indirectly by the abiotic environment. Concurrent changes in many of the resources suggest that the same environmental change may impact on more than one. Simultaneous change throughout the Benguela system indicates that environmental forcing sometimes takes place over wide geographic areas. At the northern and southern extremities of the Benguela system, responses to environmental change may be different because processes through which the change is mediated are different.