the control effluent disposal to prevent disturbances to the reef ecology. Further research should be undertaken by the concerned government agencies to determine the precise carrying capacity of the parks, whether in terms of the maximum number of users or the intensity of use by various categories of users. Establishment of an ongoing program for monitoring changes in the levels of coral covers and in the species composition of corals, fishes, and other marine organisms would be a first step towards determining the carrying capacity of Phang Nga Bay. Information on user attitudes to congestion and apparent degradation within the marine parks is also recommended. A GIS database focusing on Phang Nga Bay region should be established. Information on the location and structure of the islands, marine community structures, location of moorings, and bottom features in certain areas of the marine parks should be stored in the database. This system provides a tool to measure the effects of changing usage patterns and will assist future management decisions, in particular those relating to the establishment of an artificial reef, the location of additional mooring buoys, and the need to preclude diving from certain areas to allow marine community structures (e.g. coral) to recover