AN APPROPRIATE CARP POLYCULTURE TECHNOLOGY WITH SMALL INDIGENOUS FISH MOLA (AMBLYPHARYNGODON MOLA) FOR RURAL BANGLADESH

摘要

A fish polyculture trial with different combinations of large Indian major and Chinese carps with small indigenous fish species mola (Amblypharyngodon mo/a) was carried out in the farmers' pond at Boilor-Dhanikhola village under Mymensingh district, Bangladesh. The main objective was to develop a sustainable carp-mola polyculture technology for increased fish production as well as improved nutritional status of rural households through increased consumption of small fish. A secondary objective was toassess the nature and extent of interspecies competition and synergy among carps and mola. There were 6 treatments among which the highest fish production (2,712 kg ha~(-1)) was obtained using 5 species of carps with rohu (Labeo rohita), catla (Catla catla), mrigal (Cirrhinus mrigala), grass carp (Ctenopharyngodon idella) and silver carp (Hypophthalmicthys molitrix) along with mola in which mola contributed 0.9% (23 kg ha~(-1)) to the total production. The next highest production (2,642 kg ha~(-1)) wasobtained in 4 species of carps rohu, catla, mrigal, grass carp with mola, where mola contributed 2% (52 kg ha~(-1)). While mola production was relatively high in this combination, production of catla was reduced. All treatments having silver carp had lower, but similar production irrespective of the presence or absence of mola or grass carp. Mola competed for food with silver carp as well as catla. It exerted neutral reactions towards rohu and mrigal. From a nutritional point of view, 4 species carp polyculture with mola is recommended as it has ensured higher production of nutritionally rich mola. The large carp polyculture along with mola may be considered as a viable proposition of rural aquaculture technology for Bangladesh in terms of nutritionaland socio-economic benefits of the rural households.