The analysis of hundreds of previous studies of marine-ecosystem disease is published this month in the journal Public Library of Science Biology (available without charge at http://www.plos.org ). The report finds the rate of disease increasing in some taxa, such as in turtles, mammals, mollusks and urchins, but declining in fish.
However, says Jessica Ward, a Cornell doctoral student in ecology and evolutionary biology and lead author of the published study, "Disease in fish populations is decreasing only because their numbers are decreasing, due to over-fishing and other factors."
Says Ward, "Undoubtedly there are fewer and fewer cases of pneumonia among veterans of World War I , but that doesn't mean the veterans are becoming healthier. They are becoming fewer in number, and so are populations of wild fish."
Indeed, she notes, for many populations, there are too few fish left for disease to be observed.
The study was conducted by the 15-member Marine Disease Working Group of the National Center for Ecological Analysis and Synthesis, a Santa Barbara, Calif., ecology think tank. Heading the marine disease group is C. Drew Harvell, a Cornell professor of ecology and
evolutionary biology. She comments: "This is the first quantitative study to provide solid evidence that rates of disease do seem to be increasing in the ocean. It has been hard to tell if disease is increasing because we didn't have proper baselines. It's been much tougher to understand the frequency of marine disease than it is to monitor for SARS , for example, because the ocean is out of sight and out of mind
Contact: Roger Segelken
Cornell University News Service