Abstract. Data on reef benthos has been annually collected on Chumbe, Bawe and Changuu reefs close to Zanzibar, Stone Town, since 1992. The data shows that the El Niño in the Indian Ocean in 1997/1998 reduced the coral cover on most reefs with up to 30%. After the El Niño, a slow recovery was noticed until a major Crown-of-Thorn Starfish (COTS) outbreak occurred in 2002/2003 followed by a dramatic decrease in live Acropora cover. Only one of the reefs shows an exception – the protected Marine Sanctuary on the western side of Chumbe Island. When the first COTS were seen, the park management immediately initiated an on-going COTS removal programme, which has had a significant positive impact on the reef recovery. On the protected reef, the percent cover of live coral is back on the same level as before the bleaching event. Manual COTS removal programmes are often seen as a waste of time and resources, as their impact are often short term. But the results from this study argue that in a relatively small reef area it is a viable option for maintained or increased reef health and for improving recovery prospects of coral after large natural disturbances