Evaluation of the optimum stocking density of Thai snakehead, Channa striata (Bloch, 1793) cultured in static water canvas tanks | |
| Author | Natdharisa Tadbhusinwat |
| Call Number | AIT Thesis no.AQ-20-02 |
| Subject(s) | Snakeheads (Fish) Fish culture Fish stock assessment |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Aquaculture and Aquatic Resources Management |
| Publisher | Asian Institute of Technology |
| Abstract | An experiment was conducted to determine the optimum stocking density of Thai snakehead, Channa striata (Bloch, 1793), cultured in static water canvas tanks without water exchange, and using a commercial probiotic for 45 days. Fish were stocked at a density of 15, 30 and 45 fish/m2 with 3 replications each with initial weights of 35.4 ± 3.31, 34.16 ± 5.93 and 32.8 ± 6.55 g (mean ± SD), respectively and initial lengths of 16.1 ± 0.32, 15.9 ± 0.76 and 15.6 ± 0.89 cm, respectively in canvas tanks (1 x 2 x 0.5 m; 500 liters capacity) filled with water at a depth of 0.2 m. Fish were fed daily at 3 % body weight with a commercial pellet feed containing 40% protein. The rearing tanks were supplemented with a commercial probiotic bacteria, Bacillus subtilis (1×109 CFUg-1 ) at a dose of 0.0625 g/m2 at 7-day intervals. The results showed that the final weight, final length, and specific growth rate (SGR) were significantly different (p < 0.01) among the three treatments, while the survival rate and average daily growth rate did not differ among the treatments. Fish stocked at 15 fish/m2 had the highest final weight, length, and SGR of 69.0 ± 15.06 g, 20.3 ± 1.57 cm, and 1.0 ± 0.10 % day-1 , respectively. The lowest feed conversion ratio (FCR) was obtained in fish stocked at 15 fish/m2 , followed by those at 30 and 45 fish/m2 , although the FCR between 15 and 30 fish/m2 were not significantly different (p > 0.05). The lowest feed intake was in 30 fish/m2 (0.8 ± 0.17 g/fish/day) followed by 15 and 45 fish/m2 , although these were not statistically significant. The highest net yield was recorded at the highest density, while the medium density of 30 fish/m2 produced a net yield of 626.2 ± 57.76 g/m2 which was 42% greater than that from the 15 fish/m2 , though not statistically significant. The results of water quality showed that TAN and nitrite levels were within the acceptable range, while dissolved oxygen (DO) and pH levels varied with stocking densities with the lowest values obtained in 45 fish/m2 . No significant differences were observed in TAN, turbidity, and hardness among the treatments (p > 0.05). Nitrite levels among treatments were significantly different in week 1 and 4 while alkalinity levels were significantly different in week 2 and 3. The results from the present study demonstrated that the optimum stocking density for culturing juvenile snakehead in canvas tanks is 15 fish/m2 with weekly supplementation of probiotics to the rearing system. |
| Year | 2020 |
| 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) | Salin, Krishna R. |
| Examination Committee(s) | Thammarat Koottatep;Datta, Avishek;Yakupitiyage, Amararatne |
| Scholarship Donor(s) | Ministry of Agriculture and Cooperatives (MOAC), Thailand;Asian Institute of Technology Fellowship |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2020 |