Comparisons of growth and economic performance among monosex and mixed-sex culture of mud crab (Scylla olivacea) using locally available feeds in pens in the tidal flats of mangrove forests, Bangladesh. | |
| Author | Khatun, Mst. Muslima |
| Call Number | AIT Thesis no.AQ-07-21 |
| Subject(s) | Crabs|xFeeding and feeds--Economic aspects--Bangladesh Mangrove animals--Bangladesh |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Aquaculture and Aquatic Resources Management, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. AQ-07-21 |
| Abstract | An experiment was conducted in a randomized complete block design to compare growth and economic performance of monosex and mixed-sex culture of mud crab (Scylla serrata) using locally available feed in the mangrove tidal flat at Munshigong of Satkhira District, Bangladesh. There were three treatments each in triplicates, (A) all-male mud crab culture; (B) all-female mud crab culture and (c) mixed-sex mud crab culture. Crabs of 80-120 g in size were stocked at 0.5/m² in all pens and fed with small-size trash fish (crude protein > 60%) twice daily at 5-10% body weight per day. The water temperature, salinity, DO and pH in all pens ranged from 17 tO 26°C, 10 to 24.5 ppt, 3.84 to 7.90 mg/L and 6.1 to 9.7, respectively. Specific growth rates by weight and internal carapace width of all-male crabs were significantly (P<0.05) higher than those of all-female crabs, while specific growth rates of the mixed-sex crabs were not significantly different from those of all-male and allfemale crabs (P>0.05). Feed conversion ratio (FCR) of all-male crabs was significantly (P<0.05) better than that of all-female and mixed-sex crabs. In contrast, payback period of all-female as well as mixed-sex crab culture was significantly lower than all-male crab culture. However, there were no significant (P>0.05) differences in final body weight, internal carapace width, daily weight gain, survival rate, gross and net yields among allmale, all-female and mixed-sex crabs. No cannibalistic nature of mud crab was observed throughout the culture period. The area of rich water in mangroves (block 1) gave significantly (P<0.05) better results in terms of FCR, survival rate, gross and net yields, net margin, revenues/costs ratio and production cost of mud crab than the area of little water (block 2), while gross and net yields, net margin, revenues/costs and production cost of mud crab in the area of moderate water (block 3) were not significantly different from those in blocks I and 2 (P>0.05). There were no significant differences of payback period among blocks 1, 2 and 3. Both allfemale and mixed-sex culture of mud crab in pens were economically feasible, however, all-female crab culture is more profitable than mixed-sex crab culture due to the higher market price of female crabs than male crabs. Thus, all-female culture in rich water in mangroves could be suitable in commercial pen culture of mud crabs in Bangladesh. However, more scientific studies are needed to confirm suitable culture environment during, another seasons and in different regions. It is also suggested to assess stock of trash fish as well as formulate economical low-cost supplementary feeds and appropriate stocking density of mud crab (Scylla olivacea) for the development of pen culture in the vicinity of mangrove forests of Bangladesh |
| Year | 2007 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. AQ-07-21 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Aquaculture and Aquatic Resources Management (AQ) |
| Chairperson(s) | Yi, Yang.; |
| Examination Committee(s) | Ikejima, Ko;Amararatne Yakupitiyage; |
| Scholarship Donor(s) | NORWAY; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2007 |