Abstract:Marine bacteria are in a stable starvation condition in seawater for most of the time. Expounding the survival strategy of pathogen in marine ecosystems is helpful understanding the characteristic of epidemiology. To get a better understanding of the starvation survival strategy of pathogenic V. fluvialis isolated from diseased Epinephelus awoara, bacterial cells in logphase were suspended in natural seawater and artificial seawater and kept at 28 ℃ for starvation study. At the initial starvation stage, all of the total bacteria number, viable bacteria number and CFU number of V. fluvialis in both seawater increased remarkably, but V. fluvialis in natural seawater exhibited more increase during a longer period than the counterpart in artificial seawater. After reaching their peaks, total bacteria number of V. fluvialis remained stable, while the CFU number and viable bacteria in artificial seawater fell more quickly than those in natural seawater. Starvation of V. fluvialis both in natural and artificial seawater resulted in increase of bacterial adhesion to the E. awoara’s skin mucus at the initial stage and sharp decrease at the later stage. Starved cells showed better resistance to high temperature and UV. The lowest detection limit of starved cells detected b y indirect ELISA was higher than that of log phase cells. The result of SDSPAGE showed less cellular protein bands of starved cells than the unstarved ones. The starved V. fluvialis were less virulent to mice than the log phase bacteria. The results indicated that V. fluvialis could survive for a long time in both natural and artificial seawater, and the starved cells were less virulent and more resistant to enviromental stresses.