WHITELEG SHRIMP CULTURE PROCESS IN LINED PONDS - PART 8 & 9

V. POND MANAGEMENT – CARE AND ENVIRONMENTAL CONTROL

III. Stage 3: Second Grow-out Stage (Commercial Culture Stage 2)

The commercial grow-out phase is commonly divided into two stages:

• Stage 1: from 30 to 60 days of age

• Stage 2: from 60 days of age until harvest

1. Stage 2: From 60 days of age until harvest

1.1 Culture duration and stocking density

The second grow-out stage begins after transferring shrimp from the first grow-out stage (approximately 60 days old) until harvest.

Recommended stocking density at this stage: 100 – 150 shrimp/m².

1.2 Shrimp transfer methods

When transferring shrimp from nursery ponds to grow-out ponds, farmers should use either the drag-transfer method or direct drainage via outlet pipes.

1.3 Important considerations during shrimp transfer

• Carefully check shrimp health before transfer: shrimp must be healthy, not molting, with firm shells, no body curvature, and no muscle opacity when feeding trays are lifted.
  To reduce stress and mortality before transfer, apply SITTO C-SPARK at 1 kg/1,000 m³.

• Culture water must be well prepared to ensure stable and appropriate environmental parameters.

• Before transfer, compare environmental conditions between the source pond and destination pond (pH, alkalinity, temperature, etc.). Differences should be minimal to avoid shock.
  Apply SITTO C-SPARK at 1 kg/1,000 m³ in the receiving pond to reduce stress.

1.4 Water quality parameter management

a. Daily monitoring

During shrimp culture, regularly check:

• pH, alkalinity, and temperature twice daily (7:00 AM and 3:00 PM)

• Toxic gases (NH₃, NO₂) and other parameters at least once daily

Key environmental parameters to maintain

b. Adjustment during abnormalities

Farmers must monitor environmental fluctuations daily to detect abnormalities early and apply timely corrective measures.

Environmental adjustment methods (for 2,000 m³ water volume)

• High pH:

  • Fermented Bacillus subtilis 1090 (500 g + 4 kg molasses + 50 L water, fermented 6–8 hours)

  • Or SITTO EM: 5 L

  • Or SITTO TAKE OFF: 1–1.5 L
    Apply at 9:00 AM or 3:00 PM

• Low pH:

  • CaO lime: 5–7 kg

  • Or ULTRA-GREEN: 4 kg

• Low alkalinity:

  • CaO + Dolomite lime: 5–7 kg

  • Or ALK-BALANCE: 5 kg

  • Or ULTRA-GREEN: 4 kg

• Low salinity:

  • Crude salt: 300–500 kg

  • Or SEA-MINER: 5 kg

• Low dissolved oxygen:

  • Increase aeration and bottom air-diffusion systems

• High NH₃:

  • Bacillus subtilis 1090: 500 g

  • Or RHODO BACCIL: 5 L

  • Or SITTO YUCCA: 1 L

• High NO₂:

  • RHODO BACCIL: 5 L

  • Combine with clean water exchange

• High H₂S:

  • Bacillus subtilis 1090: 500 g

  • Or RHODO BACCIL: 5 L

  • Or SITTO YUCCA: 1 L

• Low mineral levels:

  • SEA-MINER: 5 kg

  • Or SITTO KALI-PHAST: 3 kg

• High iron (Fe):

  • SITTO POND MAGIC: 2.5 kg

  • Or SITTO TAKE OFF: 1–1.5 L

• Temperature control:

  • High: reduce feed, increase aeration, prevent water stratification

  • Low: reduce or stop feeding, increase aeration

2. Feed management and feeding practices

a. Feed selection

• Use high-quality, nutritious, easily digestible feed from reputable brands.

• Select feed size appropriate for each growth stage (based on shrimp eye size).

b. Feeding practices

• During Stage 2, use automatic feeders exclusively and adjust feed based on feeding trays (1–2 trays per 1,000 m² pond).

• Check feeding trays every hour to adjust feeding schedules.

• Daily feed additives (divided into 4 feedings/day):

  • 06:00 – SITTO VIZYM 10 g/kg + SITTO BNN-DETOX 10 g/kg

  • 09:00 – SITTO LIVER DETOX P 10 g/kg

  • 12:00 – D-MAX SHRIMP 10 ml/kg

  • 15:00 – SITTO VIZYM 10 g/kg + SITTO BLACK GARLIC 10 ml/kg

• Stop feeding at 6:00 PM.

• Feeding principle: “Low – adequate – consistent – on time.”

• Avoid feed waste; adjust immediately if leftover feed is detected.

3. Use of probiotics and disinfectants

Probiotics

Disinfectants

4. Shrimp health management

• Monitor daily behavior: active swimming, strong feeding response, clean feces.

• Regular disease testing: microscopy (hepatopancreas, gut, gills).

• Maintain alkalinity ≥120 mg/L and minerals using SEA-MINER 5 kg/2,000 m³.

• If body curvature or muscle opacity appears, apply SITTO KALI-PHAS 5 kg/2,000 m³ every 3–5 days.

• Use SITTO THIO 5000 (5 L/2,000 m³) every 3–5 days for detoxification.

• For foam and water slime, use SIREN 5 L/2,000 m³ every 2–3 days.

• Treat liner slime and fungal prevention with SITTOZYME 250 g/2,000 m³.

• Water addition must be from treated settling ponds (Chlorine 30 kg/1,000 m³, residue-free, filtered).

5. Aeration, water exchange, and siphoning

• Use evenly distributed paddle wheels and bottom aeration.

• Maintain oval water circulation with no dead zones.

• Paddle wheel operation:

  • 60–80 days: 20–22 hours/day

  • ≥80 days to harvest: 24/24

• Siphon waste 2–3 times/day (morning and afternoon).

• Water exchange:

  • 60–80 days: 30–40%/day (+15% if water quality is poor)

  • ≥80 days: 50–60%/day (+20% if necessary)

6. Harvesting

Harvest when shrimp reach commercial size: 20–30 shrimp/kg.

a. 7 days before harvest

• Stop all oxidative water treatments.

• Increase minerals: SEA-MINER 7–10 kg/2,000 m³.

• Stabilize gut: SITTO VIZYM + SITTO BLACK GARLIC, 4 meals/day.

• Increase water exchange to 60–70%.

b. Pre-harvest checks

• Healthy shrimp, strong swimming, full gut

• Water transparency: 25–35 cm

• DO >5 mg/L

c. Harvesting notes

• Harvest early morning or late afternoon.

• Harvest all at once if shrimp are strong.

• If shrimp are weak, harvest gradually and increase aeration.

d. Post-harvest treatment

• Clean ponds within 24 hours.

• Use Chlorine to disinfect pond bottom, siphon pits, and equipment.