The mud crab aquaculture program at ICAR-Central Institute of Brackishwater Aquaculture (CIBA) has achieved a notable success with the effective farming of mud crabs (Scylla serrata) in earthen ponds. In just 165 days, hatchery-reared mud crab instars, initially weighing about 2 grams, were cultivated to marketable sizes exceeding 500 grams. The initiative yielded a total production of 70 kilograms, with an average body weight of 720 grams and a survival rate of 45%, a commendable figure for this species at a density of 300 crabs per acre.
This project is part of the scheduled caste special program (SCSP) with coastal communities of Pattipulam village, Chengalpattu district, Tamil Nadu. To mark the successful harvest, a harvest-cum-field day was organized on October 5, 2024, where participants had the opportunity to see the results firsthand.
Dr. Kuldeep Kumar Lal, Director of ICAR-CIBA, underscored the growing importance of mud crab farming in addressing future seafood demands and enhancing the sustainability of brackishwater aquaculture in India. Dr. C.P. Balasubramanian, Principal Scientist and Head of the Crustacean Culture Division, shared valuable insights into the scientific methods used in mud crab farming.
Dr. P. Mahalakshmi, Principal Scientist and Nodal Officer of the SCSP program, discussed the crucial role of the initiative in supporting local beneficiaries and widening the impact of brackishwater aquaculture in coastal areas. The five-month demonstration was overseen by CIBA scientists, including Mr. R. Aravind, Dr. J.A.J. Raymond, Dr. K.P. Sandeep, and Mr. K. Anantharaja.
Mud Crab Aquaculture
Mud crab is highly valued in the export market, driving rapid growth of its culture along the coasts of Andhra Pradesh, Tamil Nadu, Kerala, and Karnataka. As per the manual on mud crabs, the main species include the larger “green mud crab,” reaching up to 22 cm and 2 kg, and the smaller “red claw,” which grows to 12.7 cm and 1.2 kg. Both are in demand domestically and internationally.
Mud crab farming primarily uses two methods: grow-out culture and fattening. In grow-out culture, juvenile crabs are raised for 5 to 6 months in pond systems, with stocking densities of 1-3 crabs per square meter. Regular monitoring is essential, and partial harvesting can start from the third month to improve survival rates.
Fattening involves raising soft-shelled crabs for a few weeks until they harden, typically in small tidal ponds. Proper preparation and fencing are crucial to prevent escapes. This method allows for multiple cycles of fattening. Crabs can also be fattened in pens or cages in estuarine waters, though this is less common.
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Feeding consists of trash fish, clams, or chicken waste, making up 5-8% of their body weight. Maintaining water quality is essential, with optimal salinity at 15-25%, temperatures at 26-30°C, and pH between 7.8 and 8.5. Harvesting should be done in the early morning or evening, ensuring crabs are cleaned and stored in moist conditions away from sunlight.
Benefits of Mud Crab Culture for Farmers
Mud crab farming can provide several important advantages for farmers:
- Increased Income: Mud crabs are in high demand, both in India and abroad, offering farmers a good source of income.
- Diverse Livelihoods: By adding mud crab farming to their activities, farmers can reduce their reliance on traditional crops or livestock, creating more stable incomes.
- Use of Coastal Areas: Farmers can make productive use of coastal and brackishwater regions that may not be suitable for other types of farming.
- Job Creation: The growth of mud crab farming can generate jobs in areas like harvesting, processing, and selling, which benefits local communities.
- Adaptability to Market Needs: Farmers can adjust their practices based on what the market needs, helping them stay competitive.
- Skill Development: Getting involved in mud crab farming often includes training, which helps farmers learn better aquaculture and sustainable practices.
- Environmental Health: When done responsibly, mud crab farming can support local ecosystems and maintain biodiversity.
This initiative by ICAR-CIBA aims to meet rising seafood demands while boosting local economies. The project promotes sustainable farming, generates employment and offers training for coastal communities. A recent harvest-cum-field day showcased these achievements and highlighted the importance of mud crab farming in diversifying livelihoods.