Feasibility study of mud crab (Scylla serrata) fattening in the mid-coastal area of Bangladesh

Abstract:

The study was conducted in the mid coastal region of Bangladesh to identify whether the area is feasible or not for crab fattening practice. There were four crab markets found in Hatiya Upazila and Nijum Dwip. The average yearly collection of crabs in this area was 890.36 tons where lower grade male crabs (100-299 gm) constituted 17.31% and lower grade female crabs (120-179 gm) constituted 27.85%. Those can be brought under fattening practice. There are three canal system covering an area of 670 ha where saline water intrution is evident. A vast area of Hatiya and Nijum Dwip was inundated with saline water. So the people Hatiya Upazila and Nijum Dwip can easily use these huge water bodies for crab fattening. The water salinity ranged from 0-10 ppt, pH ranged from 7.8-8.6 and the soil was silty-loam. The average temparature of the last three years was appoximately 26.10°C. There were three seasons: rainy season (June to September), winter season (November to January) and summer season (February to May). Avarage temparature was lower during December to February. During March to October temparature was above 25 °C. Therefore, March to October is the suitable season of crab fattening in this area. In the study area, occational crab fatteners stocked crabs generally at 2-2.5 ind./ m2 of both male and female in the farm without maintaining any ratio of them. Locally available trash fish, chewa and crab meat were used as feed for crab fattening and there were no specific feeding rate. In these farms survival rate was near 70%. A small marketing channel are existed with 3-4 middle-men. The collected crabs were supplied to Dhaka from Tomuruddin Ghat. Steamer, launch were the main vehicles of transportation. Some also transport via Noakhali sadar and some via Laxmipur, Chadpur districts. So a potential marketing system is also existed there. So, the present study revealed that this lower portion of the mid coastal region of Bangladesh is suitable for crab fattening during the month of March to October.