STATE OF CORAL-REEFS IN THE GALAPAGOS-ISLAND - NATURAL VS ANTHROPOGENIC IMPACTS

Before the 1982-1983 El Nino disturbance event low diversity coral com munities and small, actively accreting coral reefs were present on Gal apagos shallow shelves in areas protected from strong upwelling. Prolo nged El Nino 1982-1983 sea warming resulted in 95-99% coral mortality, virtually eliminating corals throughout the archipelago. The populati on size of an ubiquitous, large sea urchin species (Eucidaris thouarsi i) was unaffected by the warming event. Urchins later showed increased abundance on dead coral colonies and frameworks, and caused bioerosio n that exceeded the net calcification capacity of disturbed reefs. Kno wn human impacts on corals result mainly from anchor damage, the colle ction of corals for sale as curios, and mechanical damage resulting fr om the activities of fishermen. An evaluation of natural and anthropog enic damage to Galapagos coral communities indicates that natural dist urbances, especially strong ENSO episodes, are of greatest concern. Ho wever, rapidly increasing human pressures could exacerbate the recover y capacity of naturally perturbed coral communities.