AbstractCurrents on the South African shelf have been measured on 13 cruises since an Acoustic Doppler Current Profiler (ADCP) was installed on F.R.S. Africana in 1989. Most previous descriptions of the West Coast (Benguela) system, including the baroclinic jet currents off the Cape Peninsula and Cape Columbine, the latter clearly diverging into a dominant offshore arm and a weaker inshore arm, have been confirmed. This baroclinic flow originates along the south-western margin of the Agulhas Bank. Measurements of the inshore features of the Agulhas Current have shown strong WSW – SSW flow aligned with the bathymetry, but with significant shelf-edge north-eastward return flows. The velocity differences between the surface and depth reveal barotropic dominance in all inshore areas and over the central Agulhas Bank. The West Coast outer shelf displays variable baroclinic effects, reflecting the importance of frontal features and cross-shelf flow. SSW flow on the outer eastern Agulhas Bank appears responsible for an offshore loss of eggs from this region. The funnelling of anchovy eggs from the western Agulhas Bank to the West Coast was clear, but this "funnel" was found to have holes through which substantial loss of eggs offshore is also probable. The currents on the Agulhas Bank and the West Coast are discussed with regard to the life histories of various commercially fished species, in addition to anchovy. The study concludes that hypotheses relating environmental factors and recruitment need to consider the variety of potential options in terms of life history contained within the prevailing current system.
No takes yet. Share an insight, caveat, or question.
Boyd et al. (1992) studied this question.