Distribution of Epifaunal Biomass on a Sublittoral Rock-Reef

Abstract

Previously the author reported on the quantitative distribution of epifaunal species and individuals and their zonation on a siltstone reef located in the open ocean near Corona del Mar, California (Pequegnat, 1964) . A marked top-to- bottom reduction in numbers of species and individuals was observed to exist on this reef, and these changes were related to a reduction of wave-induced water movements from the reef's upper to lower levels. Three observations pointed to the desirability of determining the distribution of biomass over the rock-reef: (1) the populations of some species were greatest on the reef's lower levels, (2) several of the largest species with relatively small numbers of individuals occurred here, and (3) there appeared to be a shift from a preponderance of suspension-feeders at the top toward increasing importance of deposit-feeders and scavengers at the base.