COLONIZATION OF ARTIFICIAL REEFS IN BAHIA COLIUMO, CHILE

Abstract

The assessment of the colonizaron process in small artificial reefs placed on the soft, shallow bottoms of Bahía Coliumo since 1981, has shown: a) a modérate but significan! increase of the abundance of macroepibenthic organisms on the reefs relative to adjacent level bottom areas; b) the existence of a direct relationship between the number of modular structures per unit area of bottom and the abundance of these organisms; c) microhabitat selection by colonizing species, and bathymetric differences in the colonizing species and their abundance and in the rate of reef colonization. However, and in contrast with reefs built in other parts of world, no fish attraction was observed, a result which can be simply attributed to a notorious scarcity of ichthyofauna in the study area. Another clearly unfavourable characteristic of this area for habitat enhancement efforts is determined by the discharge and accumulation of solid wastes from a nearby sawmill. These efforts seem however justified, as extensive areas of the bottom along the margins of the bay still remain relatively uncontaminated.