Assessment of Nile Tilapia (Oreochromis niloticus) seed production and growout systems for small-scale farmers in Northwest Bangladesh | |
| Author | Barman, Benoy Kumar |
| Call Number | AIT Diss. no.AQ-00-06 |
| Subject(s) | Nile tilapia--Bangladesh Farmers--Bangladesh--Economic conditions Farmers--Bangladesh--Social conditions |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Technical Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. AQ-00-06 |
| Abstract | Farmer’s participatory studies on assessment of seed production and grow—out technologies of Nile tilapia (Oreochromis niloticus; GIFT strain) followed by situational appraisal of the existing tilapia production systems were carried out in the Northwest region of Bangladesh. Situational appraisal was conducted by using participatory studies in 4 areas and a structured questionnaire survey with 210 farmers in 7 areas under two broad categories of environment of the region. The studies revealed that almost 50% of total farming households had tilapias in their ponds, mainly cultured in polyculture with Indian major carps and Chinese carps. In the risk- prone, less favorable, riverine and upland dry areas tilapias were more popular to farmers. The importance of tilapias for household consumption and their better suitability for culture within a short period were emphasized. Frequent small-size ponds of poor farmers and large numbers of seasonal ponds focused lots of potential uses of tilapias for their improvement. Limitations in the production and supply of tilapia seeds in the region were identified. Appraisal studies provided useful methods to characterize socio—economic backgrounds of farming households in the region, which permitted selection of poor farmers (men and women) as trialists to carry out participatory seed production and grow-out trials of Nile tilapia. For seed production fine mesh nylon net cages or hapas to breed and nurse the GIFT strain of Nile tilapia was tested with 43 farming households in three areas (Tarala and Banara, TB, Dewnaghata, DW and Dolapara, DP). Each farmer used 12 female and 6 male brood fish and one breeding (3.0x2.0x1.0m) and two nursing (1.5x1.0x1.0m) hapas and over a 4 - 5 month period swim—up fry were collected at 15 day intervals. Except for 15 farmers in one flood-affected area, most farmers in the other two areas were able to produce a good number of fly in addition to an increase in production of food fish or fingerlings from their ponds. Mean total swim-up fry production of individual farmers in three areas, TB, DW and DP, were 4839 i 998, 3415 i 426 and 896 i 199, respectively. In two areas (TB, DW), 48% of swim-up fry survived after nursing and were mostly sold to customers: at TB 52% of swim-up fry survived after nursing, 77% of which were sold to an average of eight customers; at DW the corresponding figures were 44%, 62% and 4, respectively. Poor farming households with more dependency on income from ponds, a better pond environment, a suitable location of the pond, active participation of household members in management of hapas and ponds, fry trading and nursery operation as a profession of farmers, were shown to be major positive factors for greater production of fry, sale and income generation in the study. 4".Seed production of GIFT strain in rice-fields was tested with the participation of 19 farming households in Girai and Bahagili. One plot of each farmer was selected and 12 female and 6 male brood fish were used to produce seed for a period of 7-8 months starting in [mm and ending in amen season. Except for 2 fanning households out of 15 at Girai and 1 out of 5 at Bahagili, all were able to produce a good number of larger size tilapia fingerlings in addition to rice. Seed production was higher in the ham compared to the amon season at both Girai and Bahagili. Mean seed production by individual farmers at Girai and Bahagili in the hero season including the fallow period, were 3761 i 3112 and 3342 i 3996, respectively. For the amon season. the mean production for the two areas were 331 i 236 and 388 i- 571, respectively. The difference in mean seed production for boro and amen seasons was highly significant (p<0.01). In the amen season the production was severely affected by unusual flooding of plots. Seeds produced were sold mostly to customers, used for stocking in their ponds and rice—fields for grow-out and the larger ones were used for household consumption. For individual farmers at Girai 1364 i 2186, 191 l i 3073 and 816 i 941 seeds were sold to customers, used to stock in their own ponds or rice-field plots for grow-out, and larger fingerlings used for household consumption, respectively. The corresponding results for Bahagili were 3011 i 3873, 235 i 227 and 484 i 251, respectively. Rice-fish systems provided larger size fry/fingerlings in the early part of the season and thus were able to provide fingerlings for local grow-out farmers. Compared to hapa based seed production in ponds, the system was more efficient with larger size seed production and higher income generation. Grow—out of GIFT strain was tested in small-size seasonal ponds of farmers in five communities in two areas with participation of a total 30 farming households. Farmers chose polyculture with three different stocking densities and species combinations of 6-7 commonly cultured species, and GIFT strain as an additional species at a stocking density 0.25 fish.m‘2. A few farmers also tested monoculture of GIFT strain at 1.73 fish.m'2. All of them followed semi—intensive management with use of inorganic and organic fertilizers and regular use of local ricebran as a supplementary feed at different levels. A promising fish yield of 2.46 tonnesha'lyr'l was obtained from the combination of silver barb polyculture with GIFT strain compared to other combinations in a 6-7 month culture period. GIFT strain produced was mostly used for consumption by farming households. |
| Year | 2000 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. AQ-00-06 |
| Type | Dissertation |
| 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) | Demaine, Harvey; |
| Examination Committee(s) | Edwards, Peter;Little, David;Kusakabe, Kyoko; |
| Scholarship Donor(s) | Department for International Development (DFID), UK.; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2000 |