Factors determining the productivity ofmola carplet (Amblypharyngodon mola, Hamilton, 1822) in carp polyculture systems in Barisal district of Bangladesh

摘要

Production of the mola carplet (Amblypharyngodon mola), a small vitamin A rich fish, has the potential to reduce human malnutrition in Bangladesh. However, although efforts have been made to promote mola culture, the factors affecting its production are poorly understood. Therefore, this study was undertaken to identify factors contributing to mola productivity in polyculture systems. A total 177 farms in three sub-districts of Barisal district, Bangladesh, were surveyed. Production of carp was higher (P 0.05) in demo farms (3.42 +/- 1.64 t ha(-1)) than non-demo farms (2.49 +/- 1.46 t ha(-1)) and also differed significantly (P 0.05) by sub-district. The productivity of mola ranged from 0.08 to 0.68 t ha(-1) (mean; 0.26 +/- 0.10 t ha(-1)). Mola yields differed significantly (P 0.05) by sub-district, but no significant difference in yields was observed between demo(0.28 +/- 0.10 t ha(-1)) and non-demo (0.25 +/- 0.10 t ha(-1)) farms. Annual costs, gross income and net income were significantly different (P 0.05) between demo and non-demo farms. A Cobb-Douglas production function model was used to identify which inputs affect fish yields. Stocking density, feed inputs, labor and pond depth were found to significantly affect total fish production, whereas mola production was significantly influenced by inputs of inorganic fertilizer, mustard oilcake, the number of months water was retained in the pond, labor and pond depth. A financial analysis showed the benefit-cost ratio of mola polyculture was higher than 1, indicating the investment efficiency of this technology for rural farmers. The study indicates that application of appropriate inputs could be considered to maximize production of mola in future projects attempting to promote its culture.