RAS Vertical Indoor Crab Farming

System Design

1. Tank Design:

   • Material: Fiberglass Reinforced Plastic (FRP), PVC, or HDPE.
   • Shape: Circular or rectangular tanks with stackable or modular configurations.
   • Size:
     • Diameter: 1–3 meters for circular tanks.
     • Volume: 500–5,000 liters per tank.
   • Depth: 0.5–1 meter, with water height adjustable based on crab size.

2. Tank Configuration:

   • Vertical stacking of tanks or multi-level shelving systems for space optimization.
   • Separate tanks for different growth stages (juveniles, sub-adults, adults).

3. Water Volume:

   • Dependent on crab stocking density; typically 50–100 liters per crab.

4. Substrate:

   • Artificial platforms, sand beds, or plastic sheets to mimic the natural environment.

RAS Components

1. Filtration System:

   • Mechanical Filters: For removing solid waste.
   • Biological Filters: Nitrifying bacteria to break down ammonia and nitrite.
   • UV Sterilizer: For pathogen control.
   • Protein Skimmer: To remove organic compounds.

2. Water Circulation:

   • Pumps to maintain consistent water flow.
   • Flow rate: 4–10 liters per minute, adjustable based on tank size.

3. Aeration:

   • Air stones or diffusers to maintain dissolved oxygen levels (ideal: 5–7 mg/L).
   • Oxygenation systems for high-density setups.

4. Temperature Control:

   • Water heaters or chillers to maintain optimal temperature (24–30°C).
   • Insulated tanks to minimize heat loss.

5. Salinity Regulation:

   • Suitable for species-specific salinity requirements (typically 15–25 ppt).
   • Saltwater mixing and testing equipment.

6. Monitoring Systems:

   • Sensors for pH, salinity, temperature, ammonia, nitrite, and nitrate.
   • Automated alarms for parameter deviations.

Stocking and Growth Management

1. Species:

   • Suitable for mud crabs (Scylla serrata), blue crabs (Callinectes sapidus), or other high-value species.

2. Stocking Density:

   • 1–2 crabs per square meter, depending on size and growth stage.

3. Feeding:

   • High-protein feeds (fish, mollusks, formulated crab feeds).
   • Feeding rate: 2–5% of body weight, adjusted based on growth stage.

4. Growth Duration:

   • Juvenile to market size: 3–6 months, depending on species and water quality.

Lighting and Environment

1. Lighting:

   • Low-intensity LED lights to replicate natural light cycles.
   • Duration: 12–16 hours of light, depending on species.

2. Humidity and Ventilation:

   • Humidity control: Maintain 70–90% for optimal conditions.
   • Proper ventilation to avoid buildup of harmful gases.

3. Shelter:

   • Provide hiding spots or substrates for molting crabs.

Water Quality Parameters

1. Temperature: 24–30°C.
2. Salinity: 15–25 ppt (species-specific).
3. pH: 7.5–8.5.
4. Ammonia: < 0.05 mg/L.
5. Nitrite: < 0.1 mg/L.
6. Dissolved Oxygen (DO): 5–7 mg/L.

Advantages of Vertical Indoor RAS Crab Farming

1. Space Efficiency:

   • Vertical stacking maximizes use of available space.
   • Ideal for urban or limited-area setups.

2. Water Efficiency:

   • Recirculation minimizes water consumption.
   • Regular filtration ensures water quality.

3. Environmental Control:

   • Controlled parameters for consistent growth and reduced mortality.
   • Year-round farming independent of weather.

4. Reduced Disease Risk:

   • Pathogen control through filtration and UV sterilization.

5. High Productivity:

   • Faster growth rates and higher survival rates in controlled conditions.

Customization Options

1. Tank Sizes:

   • Customizable based on farm capacity and layout.

2. Automation:

   • Automated feeding systems.
   • Integrated monitoring and control systems.

3. Integration:

   • Combine with other aquaculture species (e.g., shrimp) for polyculture setups.