An Investigation of Coastal Water Quality and SEMBV Disease in Penaeus monodon in Coastal Southern India

Penaeus monodon infected shrimps in various size groups were randomly collected using a clean bucket from cultured ponds in all the sampling stations (Ramnad, Tuticorin, Pattukottai, Nagapattinam, Karaikal, Srikhazhi, Chidambaram, Cuddalore, Pondicherry and Marakkanam, Coastal Southern India) during the study period of four months. Infected water and specimens were also collected from the same location. Water quality data including temperature, salinity, pH, dissolved oxygen (DO), ammonia (NH3), nitrate (NO2), and nitrite (NO3) were measured at the same location as the pond along with the coastline. Infections with mesodermal and ectodermal baculovirus (SEMBV) were found in the middle intestinal gland and other organs of the cultured P. monodon at all ten sites under examination. Furthermore, SEMBV infections were found in neighboring populations. The mature grass shrimp that were obtained from Tuticorin, Karaikal, and the vicinity of Chidambaram showed significant damage compared to other regions like Ramnad, Pattukottai, Nagapattinam, Sirkhazhi, Cuddalore, Pondicherry, and Marakkanam. The highest recorded percentages were Tuticorin, Sirkhazhi, and Cuddalore (74%) followed by Chidambaram (46%). However, in the Tamil Nadu Coastal Region there was a small but statistically significant variation in the prevalence of SEMBV. The available statistics strongly suggest that white spot disease could pose a significant threat to the coastal Tamil Nadu farming community. The most common main pathogen detected throughout the survey was SEMBV, which was discovered in P. monodon samples from each of the ten survey locations. These results suggest that SEMBV is a new infectious agent present in the culture stocks of Indian Penaeid species. Many of the shrimp sampled in the survey had a few common Penaeid epicommensals on their gills, appendages, and general body surface before a few days of infection; some of these were associated with illness and even mortality.