Aquaculture Systems Based on Intensification( Intensive, Extensive methods....)

 

Aquaculture Systems Based on Intensification

Introduction to Aquaculture Intensity

• Intensity of Aquaculture: Refers to how many organisms are raised in a specific area or volume.
• Importance: Helps compare different levels of culture for a species.
• Input Requirements: Higher intensity means more inputs (like food and care) are needed for growth.

Extensive Culture

• Definition: Culturing fish in large areas with low stocking density and relying on natural feeding.
• Characteristics:
• Water quality is not managed.
• No artificial feeding.
• Minimum labor required.
• Low yield and growth rate.
• Low capital investment.

Examples of Extensive Culture

1. Pokkali Fields (Kerala):
• Traditional method combining paddy and prawn culture.
• Salinity-tolerant paddy crop.
• Cultivated in 26,400 ha in Ernakulam district.
• No fertilizers or insecticides used; nutrients come from fish and prawn excreta.
• Juvenile prawns enter fields during high tide and are harvested during low tide.
2. Bheries (West Bengal):
• Brackish water enclosures for shellfish and finfish.
• Tidal water brings in fry, which feed on plankton.
• No artificial feeding; fishing occurs from September to November.

Semi-Intensive Culture

• Definition: Intermediate between extensive and intensive cultures.
• Characteristics:
• Moderate stocking density (10,000 to 15,000 fish/ha).
• Natural food supplemented with fertilizers.
• Yield ranges from 3 to 10 tons/ha.
• High survival rates.

Intensive Culture

• Definition: High-density fish production in small areas.
• Characteristics:
• Very high stocking density (up to 1,050 fish/m³).
• Constructed ponds with well-aerated water.
• Regular water replacement and fertilization.
• Fish are fed with formulated feed.
• Yield ranges from 15 to 100 tons/ha or more.
• Examples include polyculture, cage culture, and pen culture.

Super Intensive Culture

• Definition: Also known as Ultra-intensive culture.
• Characteristics:
• Culture ponds act as vessels for high material and energy flow.
• Requires skilled management.
• High use of fertilizers and aerators for oxygen mixing.
• Very high fish stocking density.
• Commonly used for shrimp and prawn culture.
• Examples include RAS (Recirculatory Aquaculture System) and Biofloc.

Summary

• Aquaculture systems vary in intensity, affecting growth, yield, and management practices.
• Understanding these systems helps in selecting the appropriate method for fish and prawn culture based on resources and goals.