The Giant Trevally, scientifically named Caranx ignobilis, is one of the most iconic and robust predatory fish found in the tropical waters of the Indo-Pacific, including Indian seas. Popularly known among anglers as GT, this species can grow up to 170 cm in length and weigh over 80 kg in the wild. While it's a prized catch in sport fishing, in recent years, it has also emerged as a promising species for aquaculture, especially in cage farming.
Due to the efforts of ICAR-Central Marine Fisheries Research Institute (CMFRI), the breeding and seed production of this species have been achieved under captive conditions. This development opens up new opportunities for small-scale and commercial farmers looking for profitable fish species suited for coastal aquaculture systems.
Why Giant Trevally for Farming?
Giant Trevally is not only admired for its fighting spirit in the ocean but also for its culinary appeal. Its meat is firm, delicious, and rich in nutrients, making it highly preferred in domestic and export markets. In local markets, GT fetches a price of Rs. 400–600 per kg, and even more in premium seafood restaurants. With the right management, farmers can expect a good return on investment.
The species is highly adaptable to brackish and marine waters and shows fast growth when provided with proper feed. It is also hardy, meaning it can tolerate varying salinity and water conditions, reducing risk for farmers in coastal belts.
Biology and Natural Habitat
The Giant Trevally is naturally found in coral reefs, lagoons, estuaries, and even near the surf zones of islands and coastlines. It is a strong swimmer and a natural predator, feeding on fish, squid, and crustaceans.
In farming systems, this carnivorous habit means it needs a high-protein feed. However, pelletized feed designed for marine carnivorous fish is now readily available in India. GT grows quickly under the right conditions reaching marketable size (1.2 to 1.5 kg) in about 6 to 8 months in cage culture setups.
Cage Farming: A Farmer-Friendly Technology
ICAR-CMFRI has developed an affordable and practical cage culture model for Indian farmers. A cage measuring 4m x 4m x 3m can be installed in backwaters, estuaries, or coastal lagoons. The cage can be constructed with galvanized iron (GI) pipes and HDPE nets.
Each cage can stock around 1,000 GT fingerlings. With proper feed and care, farmers can harvest over 700–800 kg of fish from a single cage in 7–8 months. A survival rate of over 90% is commonly achieved when water quality and feeding are well managed.
Moreover, GT can be cultured alongside other compatible species like seabass or pearl spot, further improving profitability.
Feeding and Maintenance
Being a carnivorous species, GT requires a protein-rich diet, especially in its early stages. Farmers can use floating pellets with 35–45% crude protein or supplement with low-value fish, depending on availability and cost.
Feeding is done 2–3 times a day. The key is to avoid overfeeding, which can pollute the water. Daily observation of fish behavior during feeding time helps assess their health and appetite.
Regular cage cleaning is important to ensure good water flow. Farmers should also monitor salinity, dissolved oxygen, and temperature. While GT is hardy, prolonged stress due to poor water conditions can impact growth.
Market Opportunities and Profit Potential
Giant Trevally is in high demand in domestic seafood markets and restaurants, especially in coastal cities. Its firm meat, low-fat content, and rich flavor make it ideal for grilling, frying, or even sashimi. The fish also has good shelf life and is well-suited for chilled or frozen transport.
Farmers near coastal towns or tourist destinations can fetch a premium price. With support from government fisheries departments and organizations like CMFRI, marketing and distribution are becoming easier.
Role of Research and Government Support
ICAR-CMFRI has not only succeeded in the captive breeding of GT but is also actively training farmers across India in cage fabrication, site selection, seed sourcing, and feed management under the All India Network Project on Mariculture (AINP-M).
Farmers from several districts in Kerala, Tamil Nadu, and Andhra Pradesh have already begun Giant Trevally farming with technical guidance. Some farmer groups are even exporting to niche seafood markets.
The Giant Trevally, once only known to sport fishers and divers, is now becoming a profitable reality for Indian coastal farmers. With proper training, support, and a willingness to learn, farmers can tap into this premium fish market and significantly boost their income.
As aquaculture moves towards sustainability and diversification, species like GT offer the right balance of profit and ecological adaptability. For young entrepreneurs and traditional fishers alike, the Giant Trevally is indeed a golden opportunity from the blue waters.
