Coastal Weather Warning: Low Pressure System Over Bay of Bengal Threatens East Coast Aquaculture Belts

The India Meteorological Department (IMD) has tracked a well-marked low-pressure area over the West-Central Bay of Bengal, moving west-northwestwards toward the South Andhra Pradesh and North Tamil Nadu coasts.

The system is forecast to trigger widespread squally winds (45–55 km/h) and moderate to heavy rainfall (65 to 115 mm) across Nellore, Prakasam, Bapatla, Krishna, and West Godavari districts over the next 72 hours.

Heavy rainfall directly into open ponds creates a dense top layer of cold, acidic freshwater. Salinity can drop abruptly by 5 to 10 ppt within a 12-hour period, inducing severe osmotic shock and premature molting in Vannamei shrimp.

Persistent overcast cloud cover eliminates sunlight-driven algal photosynthesis. Phytoplankton blooms can experience sudden die-offs (crash), turning pond water brown or clear and consuming all available dissolved oxygen as dead algae decompose.

1. Feed Management: Cut all feeding rations by 50% immediately. If rain is continuous, cease feeding completely for 24 hours to prevent uneaten feed from rotting on the pond bottom.

2. Alkalinity Buffering: Broadcast Agricultural Limestone (CaCO3) @ 100 kg/acre or Dolomite @ 75 kg/acre along pond dykes before and during rainfall to buffer against acid runoff.

3. Drain Surface Freshwater: Open top-water surface drainage pipes to skim off the lighter freshwater layer without losing saline bottom water.

4. Continuous Aeration: Run all paddlewheel and long-arm aerators 24 hours a day to prevent thermal stratification and maintain DO above 4.5 mg/L.