Mangroves dominate the major part of the world's coastlines between 20 degrees north and south latitude (McGill, 1959). Because of their proximity to many areas of oil production and shipping lanes and also because of the low energy environments in which they occur, mangroves are frequently impacted by shipping accidents, oil well blowouts, etc. Although there are at least 15 genera and more than 50 species of mangroves worldwide (Chapman, 1970), species of the genus Rhizophora are of major importance in areas adjacent to open water over much of the more tropical parts of the range of mangroves. Rhizophora mangroves can be harvested for timber and firewood, they provide shelter and habitat for many animal species and they are a source of high level photosynthetic productivity that serves as an energy base for estuarine food webs. It is the food webs that are involved in the production of a variety of economically important marine and estuarine organisms such as lobsters, prawns, finfish and shellfish (summarized by Teas, 1979).