Organic Load Induced Black Gill Discoloration in Farmed Litopenaeus vannamei and its Mitigation Using a Pond Sanitizer

Abstract

White leg shrimp, Litopenaeus vannamei (Boone, 1931) is considered as a species that revolutonized shrimp farming industry in India in the recent past. There has been a marked shift from farming of indigenous black tiger shrimp, Penaeus monodon to culture of exotic white leg shrimp, L. vannamei in India from the beginning of this century. With its present performance in Asia, world production of this species will overtake all other cultivated shrimp species. Over 90% of shrimp culture in Western hemisphere is represented by white shrimp (Wurmann et al., 2004). Intensification of shrimp farming poses several problems including the sporadic occurrence of diseases in farms. In addition to the most widely occurring viral and bacterial diseases a number of less prevalent disease manifestations are also observed in shrimp farming sector. The present study deals with the observation of black discolouration of gills of farmed L. vannamei and its mitigation using a pond sanitizer. Black gill syndrome is also known as black gill disease, burned gills, black spot disease, and branchiostegite melanization. Generally there are multifocal black or brown spots in gills, or general discoloration of gills due to melanization at the sites of tissue necrosis.