Importance Of Aquaculture

Aquaculture is the fastest growing food producing sector and plays an important role in the global economic growth. Aquaculture is not only a source of food but it is also one of the main sources of income of millions of people around the world. The percentage of people engaged in the aquaculture sector in 2006 was 3.2% of the 1.37 billion people who are economically active in agriculture. Therefore, the sustainable development of aquaculture is of utmost importance for the food security and equally important for the livelihood security in the developing as well as in the developed world. Disease outbreaks are being increasingly reported as a significant constraint to the aquaculture sector, affecting the economic development of the sector in many countries, both developing and developed (Bondad-Reantaso et al., 2005). Bacterial pathogens probably cause more disease problems in aquaculture than all other causes combined (Meyer, 1991). Vibriosis is the well-known cause of severe losses, affecting fish as well as molluscs and crustaceans. Several epizootics of vibriosis have been reported worldwide (Lightner, 1996). Among the bacteria, vibrio species (i.e. bacteria belonging to the species Vibrio harveyi, Vibrio campbellii, Vibrio parahaemolyticus and Vibrio

Challenge tests will be performed according to the method developed by Defoirdt et al. (2005). Bacterial isolates used for the challenge will be washed twice in filtered and autoclaved seawater. The bacterial dose will be 105 CFU per ml of shrimp larval culture water. The survival of the larvae will be counted 48 h after the addition of the pathogens. Each treatment will be done in triplicate and each experiment will be repeated twice to see the reproducibility. The sterility of the control treatments will be checked at the end of the challenge. If the control is contaminated, the results will be not considered and the experiment will be