The role of mangroves, as nursery and feeding areas, in the enrichment of coastal waters, in the stabilization of the shoreline, and in trapping silt and wastes from upland runoff, is repeatedly being threatened by suggestions for reclamation, whether for aquaculture, agriculture, or development projects. Proposals for such alternatives should only be judged after taking into account the environmental subsidies involved, and possible losses in energy transformation steps. Assurance is needed that renewable resources and other environmental capital will not be sacrificed.