58 SEPTEMBER 2015 • WORLD AQUACULTURE • WWW.WAS.ORG species of mud crabs, including Scylla serrata, S. olivacea, S. paramamosain and S. tranquibarica, are of great commercial importance, of which the former two are available in Bangladesh. The highest populations of mud crabs are associated with mangrove forests that serve as important feeding and nursery grounds. Mud crabs are abundant in the estuaries, tidal rivers of the Sundarbans mangrove swamps and vast coastal ghers or shrimp polders along the coastal region, such as Satkhira, Khulna, Bagerhat, Chittagong, Cox’s Bazaar, Noakhali, Vola, Hatia and the Sundarbans of Bangladesh (Khan and Alam 1991, Ahmed 1992). Mud Crab Production Systems Bangladesh is well suited for mud crab production. The geographical position and climatic conditions of Bangladesh make the coastal waterbodies highly productive for mud crab production. Availability of brackishwater of optimal salinity and temperature conditions have made mud crab farming easier in Khulna and Cox’s Bazar regions. Mud crabs are less susceptible to disease and more resistant to adverse environmental conditions and climate change effects, causing many shrimp farmers to transfer to mud crab farming. The present culture system of mud crab mostly involves fattening of immature (having underdeveloped gonads) and/or underweight (<80 g for female and <100 g for male) mud crab to produce market-size hard-shell crabs, which are then exported live. The fattening operation includes stocking crabs in brackishwater ponds/ghers (enclosures) for a very short period (around 7-10 days) with supplementary feeding. Different types of locally available trash fish are used as feed. Another culture system includes producing soft-shell crabs Mud crab farming is gaining popularity in coastal districts of Bangladesh, owing to the good demand and better price in the international market. Mud crab has emerged as a potential exportable commodity and a means of livelihood for poor members of coastal communities in Bangladesh. According to a study by Molla et al. (2009), the mud crab fishery supports the livelihood of more than 50,000 fishers, traders, brokers, transporters and exporters in Bangladesh and the number has increased to about 300,000 households at present. Mud crab is popular as a palatable and valuable food item globally. It also has a good nutritional value. It contains, on a wet weight basis, 15-25 percent protein, 1 percent fat and 2-3 percent minerals (Huq et al. 2015). It is thought to have some medicinal value; it has been used traditionally to cure some diseases. Mud Crab Market Demand The growing demand for mud crab in Asia, Europe and America has stimulated an increase in mud crab production. About 7,000 t of mud crab was produced in 1995-1996 (Kamal 2003) and more than 10,000 t was produced in 2000 (Salam et al. 2012) in the southwestern districts of Bangladesh. Mud crabs have become the second-most exported crustacean product from Bangladesh. It is exported live to China, Taiwan, Thailand, Singapore, Malaysia, Japan, Hong Kong, South Korea, Japan, the USA and various countries of Europe. Total earnings from mud crab export in 2007-2008 was US$7,068,000 (Ferdoushi et al. 2010). There has been an increase in crab export earnings from 2009-2010 to 2013-2014. A major portion of mud crab export comes from catching crabs in the estuaries, tidal rivers and mangrove forests of the Sundarbans, while some portion comes from fattening. Four Mud Crab Aquaculture: Present Status, Prospect and Sustainability in Bangladesh Md. Sahidul Islam, Naseem Ahmed Aleem, Muhammad Meezanur Rahman TOP, FIGURE 1. Soft-shell mud crab (Photo: Md. Sahidul Islam). BOTTOM, FIGURE 2. A soft-shell mud crab farm in Teknaf, Cox’s Bazar, Bangladesh (Photo: Md. Sahidul Islam).
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