, Diagnosis an-&& of Shrimp Diseases - Central Institute of ...

SI-IRXMP DISEASES: GENEIL4L ASPECTSS. V. Alavandi and T.C. SantiagoIntroductionCoastal aquaculture, especially shrimp aquaculture has undergone a fast growth inrecent times in India. While traditional type of shrimp farms were being improved, newextensive and semi-intensive farms were being established at rapid pace. Majority of theinvestors ventured into aquaculture by initially familiarising themselves with technical aspectsof site selection, pond design, feeding techniques, intensive stocking etc. More often, thesignificant impact of disease was overlooked. However, concomitant with the rapid expansionand intensification of shrimp farining activities serious disease outbreaks were of frequentoccurrence.Attention to disease problems was paid only when widespread outbreak of diseasealarmingly reduced the profit from shrimp farming projects. It has become essential for shrimpfarmers to understand the biological and environmental factors that lead to diseasedevelopment, the maladies fiat can cause considerable loss to cultured shrimp, the earlydetection of incidence of diseases and drawing up farming strategy that would minimise orprevent the onset of diseases.What is disease and how diseases develop?As any other living organisms, shrimp also have specific physiological functions forgrowth and development, which is greatly influenced by various factors of the environment inwhich they are living. Any impairment in the physiological functioning may lead to abnormalcondition of an organism, and this phenomenon is known as disease. However, many expertsconsider that there are 3 factors, which interact with each other and result in the occurrence ofdisease. These factors are the host (shrimp), the environment and disease-causing organism(pathogen). Therefore, disease can be described as an expression of complex interaction ofhost, pathogen and environment (Fig. ).A decline in llost's immunity is the main cause of disease. A lot of factors will impairshrimp health and the most important pre-disposing factors leading to diseases in shrimpculture are:I. Adverse environment11. High stoclting density with limited water exchange facilities111. Nutritional deficiencyipoor nourishment