Aquaculture Disease Diagnosis and Health Management

Aquaculture is growing by leaps and bounds and is one of the world’s fastest-growing industries in food production. Unlike other terrestrial farm animals and plants, aquatic animals require more attention in order to monitor their health. They live in a complex and dynamic environment and are not readily visible except under tank-holding conditions. Similarly, feed consumption and mortalities are also equally well hidden under water (Bondad-Reantaso et al. 2001). So the problems faced by the aquatic animals are also species and system specific. The complexity of the aquatic ecosystem makes it difficult to understand the difference between health, suboptimal performance, and disease. The range of diseases found in aquaculture is one among the major problems faced by aquaculturists all over the world. Diseases in aquaculture are caused by the outcome of a series of linked events involving the interactions between the host, the environment, and the presence of a pathogen (Snieszko 1974). Environment includes not only the water and its components (such as oxygen, pH, temperature, toxins, and wastes) but also the kind of management practices (e.g., handling, drug treatments, transport procedures, etc.). There are three factors such as stocking density, innate susceptibility, and immunity which are particularly important in affecting host’s susceptibility to diseases. The intensive shrimp aquaculture has parallely brought disease problems leading to great economic loss. Diseases may be caused by a single or combinations of multifarious factors. Generally, diseases are broadly classified in to infectious and noninfectious. The former is caused either by virus, bacteria, fungi, parasites, or rickettsia, while the latter is due to environmental stresses, genetic factors, and nutritional deficiencies. The most important steps to reduce or prevent losses due to diseases in aquaculture are monitoring as regularly as possible and appropriate action at the first sign(s) of suspicious behavior, lesions, or mortalities. These fundamental approaches should be followed in many aquatic animal production sectors as in animal husbandry and agricultural production. Some farmers hesitate to reveal the disease problems due to their ignorance that it may result in failure in the competitive market price. It should be made understood that hiding or denying health problems can be as destructive to aquatic animals as it is elsewhere.