Carp–mola productivity and fish consumption in small-scale homestead aquaculture in Bangladesh

Small indigenous species (SIS) of fish such as the mola carplet (Amblypharyngodon mola) are rich in nutrients, often containing high levels of zinc, iron, and vitamin A. Despite scientific and government efforts, culture of SIS for improved nutrition is not yet widespread. This paper investigates the contribution of the mola carplet, commonly referred to in Bangladesh as “mola” to household fish consumption, and the factors influencing productivity and income from carp–mola polyculture in southwest Bangladesh. In addition, we assess the effect of inclusion of mola into carp polyculture ponds on the inputs required to culture fish in homestead ponds. Carp–mola polyculture farmers (n = 344) and carp-only polyculture farmers (n = 513, as controls) were surveyed in May 2013. Mola broodstock were stocked in 4881 homestead ponds, at an average rate of 25 kg ha−1. The results indicated that pond area, water color (a proxy of phytoplankton abundance) and inorganic fertilizer (primarily urea and TSP) significantly influence mola production. Smaller ponds proved to have higher productivity than larger ponds. Production and profitability of carp–mola polyculture system are significantly higher (P < 0.1) than carp-only polyculture systems. Mola also contributed to household fish consumption, with 47 % of mola produced in homestead ponds consumed by household members. The results suggest scope for wider dissemination and impact of mola production technology. Such dissemination might involve closer collaboration among research, governmental, and non-governmental organizations, involving lead farmer selection, farmer-to-farmer visits and result demonstrations and wider communication of the positive outcomes of culturing mola.