The study found increased reports in scientific literature of disease outbreaks for turtles, corals (non-infectious bleaching), mollusks, mammals and urchins, said Dr. Kevin Lafferty, a USGS marine ecologist in Santa Barbara, Calif., and coauthor with Jessica Ward, a graduate student at Cornell University. The scientists detected no significant trends for seagrasses, decapods, corals (infectious disease) and sharks/rays, and, most surprisingly, they found evidence of decreased reports of disease outbreaks in fishes.
Although stress may make individuals more susceptible to disease, disease outbreaks are also associated with dense populations, which aid in transmission of disease between individuals of a species, said Lafferty.
"Infectious disease should increase in thriving populations as much or more as in stressed populations. Probably the most alarming result of our study is the suggestion of fewer diseases in fishes. As we fish stocks down, the remaining individuals may be too sparse to transmit infectious diseases," said Lafferty.
The USGS scientist noted that this research would not have been possible until a couple of years ago because the extensive databases on scientific research now allow scientists to use the data from previous research efforts to test scientific hypotheses, including trends in population status perhaps attributable to specific factors.
"Ideally we would have complete records of disease outb
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Contact: Catherine Puckett
catherine_puckett@usgs.gov
707-442-1329
United States Geological Survey
14-Apr-2004