An ecological approach to human impacts on and conservation of marine habitats and species, with a tropical emphasis. It will describe the ecological effects of overfishing, nutrient enrichment, habitat loss, pollution and marine introductions. The subject will examine the meanings of the terms `rare' and `endangered' for marine organisms and the threat of extinction. Current practices employed in the conservation and management of marine habitats and endangered marine species will be debated. A central focus will be the ecological principles and practice of designing marine reserves, enhancing populations of rare species and restoring damaged biological communities. Tutorials and an on-line chat room will facilitate the debate of all current issues in marine conservation.