The rainy and stormy season always brings major fluctuations in water conditions in ponds, lagoons, and aquaculture cages and rafts. Sudden changes in temperature, pH, dissolved oxygen, or turbidity not only shock aquatic species but also create favorable conditions for pathogens to develop, causing serious losses for farmers.
The article below summarizes important solutions to help farmers reduce risks, stabilize the farming environment, and improve production efficiency during the rainy and stormy season.
1.PREPARING PONDS AND CAGES BEFORE THE RAINY AND STORMY SEASON
Inspecting and reinforcing pond and cage systems before the rainy and stormy season plays a key role in minimizing damage.
Ponds and lagoons
- Inspect pond embankments, reinforce weak points, and ensure the banks are higher than the surrounding ground to prevent rainwater from flowing into the pond.
- The overflow drainage system must be kept clear to reduce flooding.
- Add vitamin C and probiotics to feed to boost resistance and help aquatic species withstand shock when environmental conditions change.
Culture cages and rafts
- Replace old nets, check mooring ropes and cage floats, and retie them securely.
- Move cages and rafts to sheltered locations with gentle currents to reduce the impact of storms.
- Increase nutrition, especially vitamin C and probiotics, to improve the health of the stock.
2.TREATMENT MEASURES AFTER HEAVY RAIN AND FLOODING
For ponds and lagoons
- Drain off some of the surface water to reduce the amount of diluted rainwater, while operating paddle wheels and aerators to limit stratification and increase dissolved oxygen.
- When pH drops and the water becomes turbid, spread lime powder around the pond banks (20–30 kg/1,000 m²) and apply additional lime to the pond to stabilize pH, alkalinity, and reduce turbidity.
- Continuously monitor environmental indicators (pH, oxygen, clarity) and the health status of the aquatic stock for timely adjustments.
For cages and rafts
- Check water quality in the cage/raft area, ensuring it is within acceptable limits before returning them to the main farming site.
- Repair and clean nets, mooring ropes, and cage floats.
- Regularly observe fish health to detect abnormal signs early.
3.DISEASE PREVENTION FOR AQUATIC SPECIES DURING THE RAINY AND STORMY SEASON
Environmental management
- Observe fish and shrimp regularly. When they come to the surface, identify the cause, such as oxygen deficiency or environmental changes.
- Increase aeration, reduce feed, replace part of the water, and apply lime after water exchange.
- Monitor water level and water color; adjust feed amounts when weather changes suddenly.
Maintaining pond stability
- Apply lime periodically according to the cultured species to keep pH and alkalinity stable.
- Example: tilapia farming – 1–2 kg/100 m³ of water every 7–10 days.
- Use zeolite during the last 3 months of the culture cycle to absorb toxins (NH₃, H₂S) and heavy metals at a dose of 1–2 kg/100 m³ or every 10 days.
For cage/raft fish farming
- Hang lime powder bags to disinfect the water and destroy pathogens.
- Dosage: 2–4 kg/10 m³, with the bag suspended at 1/3–1/2 of the water depth below the surface.
Boosting resistance
- Add vitamin C to daily feed.
- Example: tilapia 50–60 mg/kg fish/day.
- Use probiotics and enzymes as directed to support digestion and protect the intestines.
- Use squid oil to coat feed to improve adhesion and stimulate feeding (10 g/kg feed).
4.COMMON DISEASES AND HOW TO HANDLE THEM
Trichodina disease
- Signs: fish produce a lot of milky white mucus, come to the surface, and rub against objects.
- Treatment: salt bath with NaCl 2–3% for 5–15 minutes or use CuSO₄ 3–5 ppm.
Fish louse disease
- Symptoms: lice attach to the body, causing itching and skin damage.
- Treatment: iodine 2 g/m³ for 3–5 days; combine with feeding Oxytetracycline 5 g/kg feed.
Red spot disease (scabies)
- Fish become sluggish, and white-gray or dark black lesions appear on the body.
- Treatment: Formol 25 ml/m³ for 3–5 days; combine with Oxytetracycline and vitamin C supplementation.
Bacterial diseases
- Signs: fish lose orientation, show hemorrhaging around the mouth and fins, or bulging eyes.
- Treatment: mix Erythromycin or Oxytetracycline into feed at a dose of 2–5 g/100 kg fish/day for 3–7 days.
CONCLUSION
The rainy and stormy season puts great pressure on the aquaculture environment, increasing the risk of disease outbreaks. Proactively preparing pond and cage systems, properly handling heavy rain according to technical guidelines, and applying appropriate disease prevention and treatment measures are key to minimizing losses, ensuring biosecurity, and maintaining aquaculture efficiency.
NT
Source: tepbac.com
