The problems are occur-ring at all depths, and the numbers of species affected is increasing as well as the number of individuals. It's definitely on the rise. Fewer than a dozen of the new diseases even have names and those with names are still in the process of being docu-mented, leaving biologists to rely on word of mouth to keep the growing number of maladies straight. As a result, simply recog-nizing whether a coral is healthy or sick can be extremely difficult, even for practiced researchers. Last month at a meeting of the Association of Marine Laboratories of the Caribbean held in San Jose, Costa Rica, Goreau spoke at a special daylong session devoted to coral diseases, one of the first chances researchers have had to exchange informa-tion on the problem.
Scientists say they have no idea why diseases are exploding on corals now.
Some speculate that multiple stresses, like bleaching, sedimentation and pollution, have pushed corals to the breaking point so that they are now unable to fend off diseases that they have fought off in the past. With the scant and scattered information researchers have so far on where the diseases are, there seems to be little sense to their spread, with some pristine reefs succumbing to disease while other much more polluted reefs remain healthy. Most diseases are new. They don't correlate with each other or any known envi-ronmental stress. In Bonaire, rapid wasting disease is having a devastating impact, yet the reefs there are so clean.