Effects of salinity on fertilization for tilapia culture | |
| Author | Nguyen Phu Hoa |
| Call Number | AIT Thesis no.AE-96-20 |
| Subject(s) | Fish-culture Tilapia |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science |
| Publisher | Asian Institute of Technology |
| Abstract | Experiments were conducted for 70 days to determine the effects of fertilization on red tilapia growth, primary productivity and water quality parameters in various salinities. The acclimated red tilapia were cultured in 5-m3 cement tanks at a rate of 2 fish/m2 in four salinities at 0, 10, 20 and 30 ppt. Urea and tripple super phosphate were applied in these tanks at two levels: 2.8 gN/m2/day and 0.7 gP/ m2/day, and 1.4 gN/ m2/day and 0.7 gP/ m2/day. Under high fertilizer input, the daily weight gain of red tilapia in freshwater was significantly different from other salinities (P < 0.05). The highest daily fish weight gain was obtained at 10 ppt at high fertilizer input at 1.18 ± 0.02 g/fish/day and 30 ppt under low fertilizer input at 1.18 ± 0.07 g/fish/day. With low fertilizer input, the fish growth rate increased with increasing salinity from freshwater to 30 ppt. The fish survival rate in 10 ppt tanks under high fertilizer input was highest and significantly different with the others (P 0.95). Under low and high fertilizer inputs, increasing net primary productivity with increasing individual growth was evident for red tilapia at 10 ppt saline water. The chlorophyll a concentration and primary production in freshwater tanks increased much more than those in saline water. It was more obvious under high fertilizer input. In tanks with low fertilizer input, the dissolved oxygen in the early morning was usually higher than 3 mg/l but less than 1.5 mg/l in freshwater and 30 ppt tanks under high fertilizer input. High pH level (> 10) was related to the high mortality of red Tilapia in freshwater tanks under high fertilizer input. High concentration of un-ionized ammonia nitrogen responding to high fertilizer inputs also had the effect on growth of red tilapia in 20, 30 ppt saline water tanks. The nitrite - nitrogen in all tanks did not reach to the lethal level of 0.45 mg/l until the last day before harvesting. |
| Year | 1996 |
| 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 | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Lin, Chang Kwei; |
| Examination Committee(s) | Little, David C.;Yakupitiyage, Amararatne; |
| Scholarship Donor(s) | SIDA EP; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1996 |