Observations on euphausiid assemblages of the South coast of South Africa

Abstract

A total of 24 species of euphausiid was collected during a survey along the South African south coast during January 1992. Communities over the Agulhas Bank were of low diversity and abundance and were dominated by Nyctiphanes capensis. Those at the shelf-edge were of high diversity and abundance and were dominated by Euphausia recurva and Thysanoessa gregaria. Such high diversity may be maintained by vertical segregation at night. Few species displayed obvious diet vertical migration, although N capensis may be able to maintain itself on the shelf by means of this behaviour. E. recurva appeared to feed on phyloplankton throughout the water column at night, reflecting the distribution of food.