Aquaculture Blueprint: Tech drives Coimbatore’s fish yield

Tamil Nadu produces around 2.3 lakh metric tonnes (MT) of fish per year on average. Deltaic, coastal, and river-basin districts such as Thanjavur, Cuddalore, Tiruvarur, and Erode dominate inland fish production across the State.

In contrast, Coimbatore compares poorly on a macro scale, generating an output of only 500 to 650 MT annually. This lower volume is because Coimbatore is a landlocked, rain-shadow district that is poorly endowed with major river networks. However, though Coimbatore ranks low in the sheer volume of total output, it ranks exceptionally high in targeted productivity and rapid technology adoption.

Therefore, the overall profile of Coimbatore with respect to fish production remains unique.

Though low on total water spread area, Coimbatore’s fish yield per hectare outstrips that of many traditional districts. Coimbatore has become the poster boy for the Tamil Nadu State Fisheries Department, serving as a prime model for intensive aquaculture infrastructure rather than traditional capture fishing methods.

Three stages of growth

The historical performance of fish production in the Coimbatore district can be split into three distinct phases. Firstly, the baseline period of 2014–17, when the annual output ranged from 350 to 450 MT, depended entirely on the shifting water storage levels in the Aliyar, Sholayar, and Pillur reservoirs.

Second, the growth phase post-2018, when the heavy promotion of fish production, spurred directly by the Government of India’s Blue Revolution initiatives and the Pradhan Mantri Matsya Sampada Yojana, saw the emergence of several infrastructure schemes, private farm ponds, and high-density farming practices. This pushed Coimbatore’s annual inland fish production to 569.50 MT in 2021–22.

Third, recent years saw stable performances, registering between 500 to 650 MT of fish production in the district. While occasional drops in production levels can be attributed to weak North-East monsoons leading to the drying up of seasonal irrigation tanks, the peak production years owe their performance to consistent reservoir inflow.

Current productivity levels

Management styles and the specific technology utilised have directly determined the productivity of Coimbatore’s water bodies.

Reservoirs, namely Aliyar, Pillur, and Sholayar, were traditionally open-water capture fisheries systems that yielded a modest 20 to 50 kg per hectare per year. With the introduction of modern floating cage culture technology at the Aliyar reservoir, yields have jumped dramatically to 10–15 kg per cubic metre inside active model cages.

Private aquaculture farmers and tanks managed by the District Fish Farmers Development Agency practising composite carp culture of Catla, Rohu, and Mrigal species have registered a steady, reliable productivity of 3 to 5 tonnes per hectare per year. Meanwhile, most Public Works Department (PWD) and panchayat-managed tanks remain highly seasonal and exhibit erratic productivity.

In good monsoon years, these tanks register 300 to 500 kg/ha in a short 4-to-6-month harvest cycle, which unfortunately drops to near zero during extended drought intervals.

Diversification & tech edge

While Erode and Tiruchi boast massive state-run fish seed production and rearing centres, Coimbatore is primarily a consumer of fish seeds. Coimbatore depends heavily on seed farms based in the Bhavanisagar reservoir to stock its local water bodies. Historically, Coimbatore has registered its highest production output in years when optimal, early-season fingerling distribution and systematic stocking have been successfully executed.

Species diversification away from traditional Indian Major Carps toward high-yield, climate-change-resistant species like Genetically Improved Farmed Tilapia (GIFT) and Amur carp has been increasingly seen over the last ten years. These newer species have inherently higher productivity rates within smaller water holdings.

The distinct technology-led advantage that Coimbatore enjoys in fish production is best exemplified by the modern floating cage culture technology practised in the Aliyar reservoir. While vast net sweeps across open waters typify large-scale traditional inland capture fish culture in most Tamil Nadu reservoirs, Coimbatore leads from the front by focusing on hyper-concentrated, high-density farming within highly structured enclosures.

Reforming lease and infra

To maximise this technological advantage, the absolute top priority for regional development must be a structural overhaul of lease policies and physical water infrastructure. Transitioning water body lease policies from a restrictive, short 1-year term to a longer 3-year policy will give cooperatives and private farmers the long-term security needed to invest capital in proper pond preparation, liming, and robust security measures against poaching.

Simultaneously, the TN Fisheries Department must actively partner with the Public Works Department to desilt major irrigation tanks well before monsoon cycles begin. This physical intervention will directly expand overall water-holding capacity, extending the viable fish culture period by several weeks. This structural baseline provides the necessary water stability for species like GIFT Tilapia and Amur carp to systematically reach marketable size within seasonal panchayat tanks.

Transforming markets, branding

On the commercial front, the top priority must pivot toward market modernisation to secure premium, middleman-free returns. A modern, digitised wholesale fish market featuring integrated cold-chain infrastructure will allow district fish farmers to pool their harvests, preserve quality, and effectively command better pricing.

This infrastructure should support a dedicated, aggressive "Coimbatore Fresh" brand.

Locally farmed inland organic fish, marketed as antibiotic-free and green-labelled, will leverage the high purchasing power of Coimbatore's massive urban population. Local Fish Farmer Producer Organisations can integrate directly with e-commerce grocery platforms and quick-commerce apps to drive demand directly to urban centres like Gandhipuram, RS Puram, and Peelamedu using solar-powered mobile fish vending kiosks and refrigerated vans.

Future high-growth framework

With foundational infrastructure and market security established, growth in fish production in Coimbatore can vertically scale through advanced technologies. Both the Pillur and Sholayar reservoirs should be brought under modern floating cage culture technologies to replicate the economic success of Aliyar.

Furthermore, Biofloc technology and Recirculating Aquaculture Systems need to be popularised by providing institutional credit and technical training to local farmers, as these technologies are highly land- and space-efficient while delivering exponentially higher yields per square meter. By aligning administrative reform, water expansion, and premium urban branding, Coimbatore is poised on the cusp of an empowered, highly profitable aquaculture era.

Dr Raja Selvaraju is Assistant Professor, Kongu Arts and Science College, Coimbatore; Dr M Krishnan is former Principal Scientist & Head, ICAR – Central Institute of Fisheries Education, Mumbai; and Dr Badri Narayanan Gopalakrishnan is Fellow, NITIAYOG, New Delhi