The present study investigates the protection of shrimp Penaeus monodon against Vibriosis (bacterial infection) most serious pathogens affecting shrimp industry world- wide. Diseased Penaeus monodon collected from South East Coast of Tamil Nadu Ramesh waram to Chennai (9.17 N 0 79.22 0 E, 28 13.04 N0 80.17E) to study the seasonal variation in Vibriosis infection. The study revealed that during summer season vibriosis infection were recorded. The highest Percentage of infection were recorded in Nagapattinam (7.65%) followed by the least percentage at Karaikal have been recorded (1.62%). The autumn season study revealed no Vibriosis infection highest Percentage of infection were recorded in Portnova 4.95%. The least was observed Velankanni at 2.15% The Rainy season Vibriosis infection was recorded the highest rate of infection at Mallipattinam (98.54%) least was observed at Adirampattinam (55.30%). During winter season Vibriosis infection was recorded the highest rate of infection at Nagore (49.58%) followed by least was observed at Mallipattinam (12.00%). Analysis of presumptive Vibrio count (PVC) on TCBS in infected shrimps was estimated comparatively higher than 5×10 0 CFUg-1) observed in uninfected shrimp samples.
P.monodon, Vibriosis , TCBS, Bacterial infection, seasonal variation.