Distribution and Abundance of the Lamp Urchinechinolampas Crassa(bell) 1880 in False Bay, Cape

Summary The subtidal distribution and abundance of the burrowing lamp urchin, Echinolampas crassa (Bell) 1880, was studied with respect to the topography of a benthic biogenous macro-ripple train by scuba at a depth of 12–23 m. A polar co-ordinate sampling method enabled study of the patch size (9–12 m2) and dispersion pattern, which varied with density; being regular during high density (1,09 m−2) and contagious at low density (0,24 m−2). A significant preference of urchins for ripple slopes and avoidance of troughs as a marginal habitat was found. The annual growth rate, as estimated from size frequency distributions, was 0,5 cm yr−1.