Stage-dependent vertical distribution of pelagic fish eggs on the western Agulhas Bank, South Africa

Abstract

The vertical distributions of eggs of anchovy Engraulis encrasicolus, sardine Sardinops sagax and round herring Etrumeus whiteheadi over the western Agulhas Bank, South Africa, were sampled between 0m and 100m, using an opening-closing WP-2 net, to investigate differences in developmental stages of the eggs. Distributions varied ontogenetically, and vertical dispersion indices showed that early-stage eggs of all species were less aggregated than middle- and late-stages. Most of early-stage anchovy eggs were distributed in the upper 40m, whereas those of sardine and round herring were more widely distributed down to 60m and 80m respectively. Results suggest that anchovy spawn nearer to the surface than do sardine and round herring.