Controlling oyster spat in shrimp ponds
- Oyster spat often appear in culture systems and are especially difficult to deal with while the shrimp are still small.
- Oyster spat come from the external supply water. The causes are water preparation that is not thorough enough, chlorine and potassium permanganate doses that are too low, rushing the water preparation in order to fill the pond, and hard source water. These conditions let the spat get in and develop after the shrimp are stocked.
- When oyster spat appear, pond alkalinity drops and the pond water becomes hard. This brings a risk of intestinal disease and affects moulting and shrimp growth.
What to do
- Preparing the inlet water properly is extremely important. You can use CuSO4 at 1–3 ppm to deal with mussels, bivalves and oyster spat. Then use potassium permanganate and chlorine at the full dose to disinfect the water thoroughly before supplying it to the pond for building up the water colour.
- Check the pond bottom regularly. When oyster spat appear, pay attention to alkalinity and minerals: measure them and supplement alkalinity (ALKAE) and minerals appropriately to help shrimp harden their shells quickly after moulting.
- Reduce water hardness with PREMIX EDTA at 1.5–2 kg/1,000 m³ of water or SIREN TV at 2–3 litres/1,000 m³ of water. At the same time, supplement high-dose digestive probiotics PRO GUT + AQUAMOS to keep the shrimp gut healthy and stable.
- Stabilise and manage the water colour with beneficial microbes throughout the culture period, and be ready to transfer the shrimp to another pond when too many oyster spat appear.
English text adapted from Than Vuong's original Vietnamese infographic.
