Effect of hapa size on conditioning of broodstock Oreochromis niloticus in fertilized earthen ponds | |
| Author | Ambali, Aggrey J. D. |
| Call Number | AIT Thesis no. AE-90-33 |
| Subject(s) | Tilapia Fishes--Reproduction |
| Note | A thesis submitted in partial fulfillment requirements for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The study was carried out to determine the effect of manipulating hapa size during conditioning period of female Oreochromis niloticus brood stock in fertilized earthen pond on seed production. An equal biomass of female brood fish was stocked during conditioning in each of three different sized hapas, a) 2. 72m2(High density) b) 5.29m2(Medium density) and c ) 10.78m2(Low density). The stocked biomassm2 was 0.Gkg ; 1.2-1 . 4kg and 2 . 3-2 . 5kg for low, medium and high stocking density respectively. After a period of 10 day conditioning, females were stocked in 40m~ hapas at a stocking ratio of 1:1 and allowed to spawn naturally over a period of 5 days. No significant difference in seed yield were recorded, treatments exceeded 3000 seedkg female spawned per month 40x10 per total ha pond area. but and There was a positive response to the use of conditioned males for 5 days prior to spawning on seed production. Females stocked with conditioned males produced seed exceeding 8200 per kg females spawned while those stocked with unconditioned males produced less than 8200 seed per kg female spawned . The mean clutch size was significantly(p<0 . 05) higher in the low density treatments compared to the other two treatments 1042, 804 and 839 seedfemale for low, medium a nd high densities respectively. However relative clutch size was not significantly different(p>0.05) among the three treatments 9, 9, 8 seedg female for low, medium and high density treatments . Water quality deteriorated during day 45 to 60 of the experimental period when dissolved oxygen concentration was lower than 0.5mgl in the conditioning heparin the morning. Decline in water quality coincided with drop in seed production . |
| Year | 1990 |
| Type | Thesis |
| 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 | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Little, David C. ; |
| Examination Committee(s) | Machintosh, Donald J. ;Yakupitiyage, Amararatne ; |
| Scholarship Donor(s) | ICLARMGTZ; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1990 |