Mitigating cannibalism in the intensive nursery rearing of Asian seabass Lates calcarifer (bloch, 1790) | |
| Author | Khan, Md. Shahzad Kuli |
| Call Number | AIT Diss no.AQ-22-03 |
| Subject(s) | Giant perch Seabass Cannibalism |
| Note | Khan, Md. Shahzad Kuli |
| Publisher | Asian Institute of Technology |
| Abstract | Asian seabass or Lates calcarifer is a high fecund and protandrous catadromous species that is farmed commercially around the world. Its production has expanded both in fresh and marine waters throughout Southeast Asia along with Australia since captive breeding techniques were first developed in Thailand. To date, Asian seabass nursery production has been erratic. One of the most serious problems is cannibalism which can cause massive production loss in the Asian seabass nursery phase. Different environmental and population factors can have an impact on the mitigation of this problem. An investigation of the synergistic effects of various factors as well the type of culture method, stocking density, tank colour, and dietary incorporation of supplementation (L-tryptophan) affecting fish growth, cannibalism, and survival rate of Asian seabass was done within this study. In a series of experiments conducted in tanks set up in an environment, the optimum nursery culture system, stocking density, and the optimum dietary L-tryptophan dose for maximum survival of Asian seabass with least cannibalism were the key considerations. While no significant influence regarding stocking density on the growth parameters of Asian seabass for a 45-day nursery period (p > 0.05) was observed, the growth parameters were significantly influenced by the culture system, with better growth performance of fish in a recirculating aquaculture system (RAS) than in a static water system (SWS). The total body length, wet body weight, weight gain (WG), and specific growth rate (SGR) were significantly greater in the RAS than in the SWS (p < 0.001). Significantly lower FCR (p < 0.01) and cannibalism (p < 0.001) were also obtained in RAS. When seabass fry was nursed in white and black coloured tanks at 0.5, 1.0, and 1.5 ind/L stocking densities for 45 days in a RAS, the WG, SGR, and fish survival were inversely correlated with stocking density. Better growth performance was observed at 0.5 ind./L stocking density in white tanks compared to black tanks. While black tanks were better than white tanks for reducing cannibalism, white tanks were better for feed visibility. In white tanks, fish had easier access to food, which is important for reducing aggressive behavior and increasing growth and survival. Feeding seabass fry with 1.50% of dietary L-tryptophan significantly improved the WG and SGR comparing the control diet. Significantly lower FCR was observed in the treatment of a 1.00% L-tryptophan incorporated diet. The interaction between the stocking density and the dietary L-tryptophan has significantly affected the yield, cannibalism, and survival (p<0.01) of Asian seabass. The addition of 1.00% L tryptophan to the diet at a stocking density of 0.5 ind./L significantly decreased cannibalism and increased survival without influencing food intake. The study concludes that Asian seabass fry grows better when reared in white coloured tanks, and survival can be increased by rearing the fish at a stocking density of 0.5 ind./L, fed with 1% dietary incorporation of L-tryptophan in the RAS. |
| Year | 2022 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development |
| 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) | Salin, Krishna R. |
| Examination Committee(s) | Loc, Thai Nguyen;Shrestha, Sangam;Amararatne Yakupitiyage |
| Scholarship Donor(s) | National Agricultural Technology Program- Phase II (NATP-II), Bangladesh Agricultural Research Council (BARC), Bangladesh |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2022 |