Validity of ceramic coral settlement devices (CSD: Okamoto et al. 2008) was compared with scallop shells, ceramic plates, and Coral Net^® in order to assess usefulness of artificial substratum for coral larvae. The results did not corroborate previous reports, saying the CSD to be a strong enhancer of settlement. Although the CSDs have been employed for many coral reef rehabilitation projects in Japan, a reassessment must be necessary. Larval settlement choice is highly dependent on external cues, such as crustose coralline algae and bacteria, but not associated with materials of artificial substratum. Physical characteristics of the substratum aid in fixation of the larvae after settlement. For flat ceramic plate, survival rate of larvae was higher on the vertical surface than the horizontal surface. Existence of hollow or micro-crevice on substratum enhances considerably for survivorship of coral recruits as they can avoid predation and destruction by fish and sea urchin. The best substratum should be effective not only in inducing larval settlement but also in enhancing survivorship of juvenile corals after metamorphosis. Design aspects that increase ease of out-planting operation and ability to withstand physical stresses (i.e. wave action) should also be taken into consideration.

The coral reef areas of Japan are utilized for economic activities such as marine tourism and fisheries, but there are conflicts of interest among different industries. To date, such social conflicts have occurred in many regions of Japan, and the efforts to solve the conflicts have been made by the local communities individually. In this study, five cases of such conflicts were compared to identify what kind of strategies have contributed to solving the social conflicts. The common key points for the conflict resolution were found to be; i) establishment of a committee with the participation of fishery sector and marine tourism sector, and ii) payment by the tourists (divers) to fund coastal management activities. This mechanism of payment by the tourists can be considered as a type of Payment for Ecosystem Services (PES). Here we suggest a possibility to realize more effective and participatory coastal management scheme by properly applying the concept of PES.