Vibrio sp. are bacteria that are gram-negative, rod-shaped single-celled short crooked (comma) or straight, a length (1.4 to 5.0) μm and width (0.3 to 1.3) μm, motile, and have flagella polar. According pitogo et al., (1990), Vibrio species characteristic glow. Vibrio biochemical properties are oxidase positive, fermentative to glucose and sensisif to the test of O / 129 (Logan, 1994 cit. Gultom, 2003).
Vibrio is a genus that was dominant in brackish water environments and estuaries. Vibrio bacteria commonly cause disease in animals and brackish waters. A number of Vibrio species known as pathogens such as V. alginolyticus, V. anguillarum, V. carchariae, V. cholerae, V. harveyii, ordalii V. and V. vulnificus (Irianto, 2003). According Egidius (1987) Vibrio sp. attacked more than 40 species of fish in 16 countries. Vibrio harveyii can be seen in Figure 11 and Bioluminescens can be seen in Figure 12.
Figure 11. Vibrio harveyii (Anonymous, 2000)
Vibrio sp. is a type of bacteria that can live on a relatively high salinity. According Rheinheiner (1985) cit. Herath (1996), the majority of phosphorescent bacteria are halofil that grows optimally at 20-40 ‰ salinity of sea water. Vibrio bacteria fluoresce including facultative anaerobic bacteria, which can live either with or without oxygen. Vibrio bacteria grows at pH 4-9 and grows optimally at pH 6,5 – either 8.5 or alkaline conditions at pH 9.0 (Baumann et al., 1984 cit. Herath, 1996).
The genus Vibrio is a causative agent of vibriosis disease that attacks the marine animals such as fish, shrimp, and shellfish. Vibrio species that fluoresce usually attacks the larvae of shrimp and shrimp fluoresce disease is called disease, as shown in Figure 13. The bacteria Vibrio shrimp larvae attack the secondary, namely when in a state of stress and weak, therefore it is often said that these bacteria include the type of opportunistic pathogens.
Feeding the uncontrolled accumulation of organic waste in the pond bottom, causing the formation of anaerobic layers that produce H2S (Anderson et al., 1988 cit. Muliani, 2002). As a result of the accumulation of H2S then the bacteria are opportunistic pathogens (can survive in adverse conditions). The presence of these bacteria, fungi, parasites, and viruses easily evolve and allow the emergence of diseases in shrimp (Tompo et al., 1993 cit. Muliani, 2002). Shrimp larvae were attacked by Vibrio sp can be seen in Figure 14.
Figure 13. The shrimp looked berpedar