Shoal Ecology on the Africana Voyage 018, April 1984

The objectives of this cruise were to obtain a broad picture of pelagic fish shoal distribution in relation to the prevailing mesoscale environmental features; to investigate intensively the diel shoal behaviour pattern of anchovy, pilchard and round herring, with particular reference to their feeding behaviour in relation to food supply. If time permitted the plan was to carry the investigation out in two areas of contrasting environmental features ie St Helena Bay and off Saldanha Bay. Shoals of fish close to strong environmental gradients (in a horizontal plane) will be surveyed to investigate the effect, if any, upon diel behaviour patterns on either side of the gradient. A number of extended lines, traversing the gradient will be steamed with plankton and fish being sampled on an ad hoc basis. It could well be that this investigation would be given a higher priority than the intensive survey off Saldanha.