Re-circulatory Aquaculture System (RAS) Facility

The Union Minister for Fisheries, Animal Husbandry and Dairying is set to inaugurate India’s first commercial-scale tropical Recirculatory Aquaculture System (RAS) based Rainbow Trout Aquaculture Farm & Research Institute in Hyderabad, Telangana.

About Recirculatory Aquaculture System (RAS)

• A Recirculatory Aquaculture System (RAS) is a land-based, closed-loop aquaculture system in which water from culture tanks is continuously treated and reused, allowing intensive fish farming with minimal freshwater use and controlled environmental conditions.
• RAS is different from flow-through systems, where water is used once and discharged. In RAS, water is treated and reused multiple times.
• Species Cultured: 
  • Food fish: Tilapia, Catfish, Salmon, Trout, Barramundi
  • Others: Shrimp, Prawns, Ornamental fish 

Key Features of Recirculatory Aquaculture Systems

• Closed-Loop Water Reuse The system continuously recycles water after treatment, resulting in 90–99% water reuse and significantly reducing dependence on freshwater resources.
• Mechanical Waste Removal Mechanical filtration units remove solid wastes such as fish excreta and uneaten feed, thereby preventing deterioration of water quality.
• Biological Filtration Process Biofilters containing nitrifying bacteria convert toxic ammonia into nitrite and then into relatively harmless nitrate, ensuring a safe environment for aquatic organisms.
• High Stocking Density RAS supports high stocking densities by maintaining optimal water quality, which leads to higher productivity per unit area.
• Controlled Environmental Conditions The system allows precise regulation of temperature, pH, dissolved oxygen and salinity, enabling consistent and year-round aquaculture production.

Limitations of RAS

• High initial capital investment
• Requires skilled manpower and uninterrupted power supply

RAS vs Traditional Aquaculture

About Trout farming

• Trout farming is the practice of raising trout in controlled freshwater systems for food, restocking rivers, or sport fishing. 
• It is common in cool regions because trout need clean, cold, oxygen-rich water.
• Environmental Requirements:
  • Temperature: Generally 10–18°C
  • Water quality: High dissolved oxygen, low turbidity
• Common trout species
  • Rainbow trout: Most widely farmed. Fast growth and adaptable.
  • Brown trout: Slower growth, higher market value in some regions.
  • Brook trout: Sensitive to water quality, usually small scale.

Government Initiatives Supporting Recirculatory Aquaculture System (RAS)

• Pradhan Mantri Matsya Sampada Yojana (PMMSY): It is the flagship government scheme promoting sustainable aquaculture in India, under which Recirculatory Aquaculture System (RAS) technology is actively supported to modernise the fisheries sector and enhance productivity.
• Financial Assistance: Under PMMSY, the Government offers central financial assistance for establishing RAS units, with up to 40% of the unit cost subsidised for general category beneficiaries and 60% for Scheduled Castes, Scheduled Tribes and women beneficiaries.

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Cold Water Fisheries in India

• Emerging High-Potential Segment: Cold water fisheries are gaining importance due to rising demand for premium species, export potential, and adoption of sustainable technologies.
• Traditional Geographical Concentration: Trout farming has historically been concentrated in Himalayan and hill states such as Uttarakhand, Himachal Pradesh, Jammu & Kashmir, Arunachal Pradesh, and Sikkim, utilising snow-fed streams.
• Seed Production Expansion: The Department of Fisheries has achieved annual production of 14 lakh trout seeds through the establishment of new hatcheries.
• Institutional Collaboration: Uttarakhand signed an MoU with the ITBP under the Vibrant Villages Programme to support trout supply and livelihoods.

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