THE SCIENTIFIC ISSUES SURROUNDING REMOTE DETECTION OF SUBMERGED CORALECOSYSTEMS

According to the 1993 colloquium on the 'Global status of coral reefs' , our understanding of the global role of coral reefs is inadequate. T o increase our understanding, an accurate large-scale mapping and moni toring programme is necessary. Historically, coastal zones have been m apped using traditional surveying tools such as topographic maps, naut ical charts, existing aerial photographs and direct observations. Alth ough less expensive than digital imagery, exclusive use of these tradi tional tools may not be practical for monitoring large or remote coral reef ecosystems accurately. Researchers are attempting to develop an adequate coral reef mapping system based on digital remote sensing, bu t are impeded by issues such as effects of the intervening Mater colum n and spectral distinction of bottom types. The two variables discusse d, which will contribute to our understanding of the global role of co ral reefs, are: I) remote sensing of submerged coral reefs in general; and 2) remote sensing of coral bleaching in particular. A summary of radiative transfer theory is presented and case studies of attempts at mapping remotely the geographic extent and health of submerged ecosys tems as well as a discussion of the remote estimation of water depth a nd quality. Problems in the translation and delivery of information to the end user are presented, and possible solutions suggested.