St Helena Bay southern Benguela Current Latitude:   -32.5000     Longitude:   18.0000 Associated Investigators: Hans Verheye   The Benguela Current ecosystem is one of the world s four productive upwelling regions of the eastern boundary current systems (Figure 1), which all have experienced substantial, decade-scale foodweb changes over the past decades. These changes are inter alia reflected in extensive fluctuations in fish yields and regime shifts of pelagic fish populations (Figure 1, insets). Retrospective analysis of zooplankton archives from both the northern Benguela, off Namibia, and the southern Benguela, off South Africa, reveal that decade-scale trends are also manifested in long-term variations in the abundance, distribution and species composition of coastal zooplankton. A pilot study of long-term changes in coastal zooplankton in the southern Benguela was undertaken under the auspices of the Benguela Ecology Programme (BEP), based on collections from several fisheries-oriented sampling programmes since 1951 on South Africa s pelagic fish recruitment grounds in St Helena Bay (Figure 2, 32.5 S). There was an initial increase in autumn zooplankton (e.g. in terms of total copepod abundance and biomass) between the 1950s and mid-1990s, followed by a marked decline (Figure 3). These changes were accompanied by marked long-term variations in community structure and coincided with fluctuations in pelagic fish recruitment and shifts in species dominance. Retrospective analysis of an extensive historical plankton collection (SWAPELS) from the central/northern Benguela off Namibia during the 1970s and 1980s was recently initiated under the BENEFIT (Benguela Environment Fisheries Interactions and Training) Programme and subsequently fast-tracked under the BCLME (Benguela Current Large Marine Ecosystem) Programme (Figure 4). The initial focus of the analysis is on samples collected on the traditional fishing grounds off Walvis Bay (23 S) during SWAPELS and other fisheries-oriented and environmental monitoring programmes (Figure 5). Although reconstruction of this zooplankton time-series is ongoing and the data base is gappy and therefore limited, there nevertheless seems to be evidence of a decade-scale, oscillating pattern in the northern Benguela zooplankton as well (e.g. in terms of total zooplankton biovolume; Figure 6). Initially, zooplankton off Walvis Bay tended to increase from the late 1950s until the late 1970s, when a reversal occurred and zooplankton declined until the late 1980s (Figure 6, sub-a). This decline then reversed back and zooplankton has since increased until the present, a trend opposite to that observed in the southern Benguela (Figure 6, sub-b, e.g. in terms of copepod abundance). Detailed studies of changes in species composition and abundance at other latitudes within the Benguela region are underway, concurrently with an analysis of fluctuations in environmental and fisheries parameters.