Improved Shrimp Growout Systems for Disease Prevention and Environmental Sustainability in Asia

Abstract

Although a large portion of the world's farmed shrimp is produced in Asia, shrimp culture operations do not succeed over the entire area. There have been several problems and impediments that are yet to be resolved. One of these problems is disease. Several shrimp diseases have threatened shrimp production, but the most devastating ones are the viral diseases, namely, yellow-head virus (YHV), and White Spot Syndrome Virus (WSSV). At present, there is no curative procedure for the two viral diseases. As such, preventive measures are thought to be more practical. Several preventive measures have been studied and introduced, but the most acceptable one is the improvement of growout systems. Asian shrimp culture employs three shrimp culture techniques: the extensive, semiintensive, and intensive systems. Beginning with the extensive about 3 decades ago, parts of this system were modified into a semiintensive system in 1980, and later the intensive type was introduced. The extensive type evolved from the hunting and gathering of food by the nearshore communities. Mangrove environments were modified into trapping ponds for livestock during the stormy months. This system uses low technology and requires vast and low-lying areas, such as mangrove forested areas. The intensive system uses higher technology, requires a smaller area, and higher elevations. Thus, it does not require mangrove areas, but it is suitable for areas behind the mangroves. The production is quite high when compared with the two other systems. Because of the high stocking density and intensive feeding, however, this type of shrimp culture is faced with several problems, such as coastal pollution caused by the farm effluent and disease problems. The intensive system was later modified to a more biosecure system, that is, a closed recirculating water system, a reduced or zero water exchange system, and shrimp culture at inland locations away from coastal influences. These innovations have made shrimp culture more efficient in controlling diseases, more sustainable, and more environmentally friendly.