ABSTRACT
Vibriosis, a disease caused by different Vibrio species, is one of the major threats affecting fish and shellfish mariculture worldwide (Lightner, 1988; Austin and Austin, 1993; Hjeltnes and Roberts, 1993). One of these species, Vibrio hllrveyi occurs naturally in warm marine waters , as also on the surface and in the gut of marine aquatic animals (Ruby and Morin, 1979). The occurrence of vibriosis in penaeid shrimps is generally influenced by factors such as stress, environmental contamination, and high counts of potentially pathogenic bacteria (Chen, 1992; Nash et al., 1992; Mohaney et al., 1994; Ruangpan et al., 1995). High mortality of larvae and juveniles of the tiger prawn (P. monodon) associated with luminiscent V. harveyi has been observed in hatcheries or farms in India (I<arunasagar et al., 1994), Thailand ijiravonichpaisal et al., 1994), Australia (Pizzutto and Hirst, 1995), Taiwan (Chen et al., 1992), Indonesia (Sunaryanto and Mariam, 1986) and Philippines (Baticados et al. 1990).
