Aquaculture in India has seen remarkable growth and transformation, making the country one of the world’s largest fish producers. Currently, India is the second-largest producer of farmed fish globally, contributing significantly to food security, employment and economic growth. Aquaculture accounts for a substantial portion of India’s agricultural exports, with shrimp farming as a leading contributor. The increasing population, with rising consumption rates, has increased the global demand for fish as a rich source of protein. This has led to intensification characterised by higher stocking densities and increased use of external inputs, such as feed, chemicals.
This also raises concerns about the possible risk of disease and infection, to prevent which antibiotics are routinely used in aquaculture settings. Subsequently, the adoption of innovative and improved fish farming approaches is also happening.
India’s aquaculture sector has increasingly adopted Biofloc Technology (BFT) and Recirculating Aquaculture Systems (RAS). These practices, while on one hand offer the advantages of intensified production, sustainability and reduced environmental impact, but on the other they also are able to keep away diseases. The Department of Fisheries, Government of India, is promoting and encouraging the adoption of these approaches among farmers by providing subsidies through various schemes at national and state level.
The Indian scientific community, such as ICAR-Central Institute of Freshwater Aquaculture (CIFA) and ICAR-Central Institute of Brackishwater Aquaculture (CIBA), are also actively researching on different aspects of using BFT and RAS. There are some success stories emerging as well as part of their engagement with farmers on the ground.
To know more about these and gain insight into how these technologies are functioning on the ground, the Delhi-based think tank Centre for Science and Environment visited some of the leading fish-producing states of India, including Andhra Pradesh, Odisha, Uttar Pradesh and Haryana, and engaged with state fisheries departments, scientific community as well as aquaculture farmers implementing these technologies.
What are BFT and RAS technologies?
BFT is a closed tank-based fish farming approach which cleans the water in fish tanks by using beneficial bacteria (known as floc). Heterotrophic bacteria (commonly Bacillus, Pseudomonas, Nitrosomonas, Nitrobacter, Acinetobacter, and Alcaligenes) are used to convert organic waste (such as uneaten feed and fish waste) into microbial biomass, which can then be consumed by the fish or shrimp.
This process keeps the water clean without needing to change it often and at the same time reduces the risk of disease as well in the fish. Water stays cleaner, hence farmers do not need to depend on external use of chemicals or antibiotics. BFT also saves money on feed, as fish can get extra nutrients from the recycled waste, making it sustainable, cost-effective and environmentally friendly for fish farming.
The inbuilt aeration system to maintain adequate dissolved oxygen levels to promote microbial activity, along with mechanical filtration reduces chances of infection. The microbes, as part of biofloc, compete with infectious pathogens for resources, limiting the latter’s growth and proliferation. It is more suitable for small farmers with limited land as it can be established in a small area and even set up for backyard farming. However, it is associated with challenges, including high costs.
RAS is also a closed-loop tank-based farming that recycles water after filtration. RAS filters and cleans the water in the tank, removing waste and keeping it safe for the fish to live in.
It has automated set up of culture tanks with both mechanical and biological filtration units, and effectively prevents the entry of pathogens from external sources. It requires the minimal interventions to assess the culture, water and disease monitoring, which allows for improved biosecurity. So, fish are less likely to get sick and need for disinfectants or antibiotics is thereby reduced.
The RAS approach also offers a controlled environment for factors like temperature, oxygen levels and cleanliness, ensuring optimal conditions for healthy fish growth. It can be set up indoors or in areas without natural water sources, allowing fish to be raised closer to cities and where demand is high. Interestingly, BFT and RAS also contribute to freshwater conservation through recycling.
But these technologies come with their own set of limitations and challenges as well. The initial investment for setting up BFT systems can be as high as Rs 4-5 lakh. Daily monitoring is required to maintain water quality and carbon-to-nitrogen ratio (to support microbial growth), which farmers often struggle with. Additionally, the level of flocculation must be monitored and adjusted every 2-3 days.
We also learnt that limitations can vary from place to place and depend on factors like availability of resources, seasonal variations, breed being reared. In Ghaziabad, Uttar Pradesh, for instance, farmers talked about inability to rear Indian Major Carps like rohu, catla in BFT systems which are in actual demand in the market. Only specific species such as pangasius and catfish are successful in case of BFT in the northern region.
In Uttar Pradesh, farmers talked about the window for fish farming being small — only 7-8 months, as November to March remain extremely cold. In Odisha, farmers appeared to be more aware and trained for use of heating rods to maintain water temperature during winter.
We also encountered farmers in Haryana who started with BFT but have now given it up and gone back to pond-based fish farming. RAS, also requires significant initial investment and operational costs, much higher than BFT. While this raises concerns about affordability for small farmers, stakeholders in the sector acknowledge that despite high initial setup costs, this approach can be financially balanced over a few years due to its comparatively higher production rates than pond and biofloc systems.
Given the high cost of establishment, only farmers who are able to avail subsidies can afford to operate these technologies for farming. Interaction with farmers from Andhra Pradesh, Odisha and Haryana suggest that subsidies provided are not sufficient in numbers for each district. In Haryana, farmers highlighted concerns regarding added operational cost due to need for constant power supply, with backup electricity needed in case of power outages. The need for more training was also voiced by farmers as the system requires continuous monitoring, management of water quality parameters and maintenance and proper functioning of filters and other equipments.