Effects of the filter feeder silver carp and the bottom feeders mrigal and common carp on small indigenous fish species (SIS) and pond ecology

A sustainable semi-intensive pond aquaculture technology including major carp species as cash-crop and small indigenous fish species (SIS) as food for the farmers' families is being optimized in Bangladesh. The inclusion of silver carp (Hypophthalmichthys molitrix), a cheap large species affordable by poor farmers, is now being considered. As part of a study on the effects of this filter feeder on polycultures including the SIS punti (Puntius sophore) and mola (Amblypharyngodon mola), an experiment was carried out in the ponds of the Bangladesh Agricultural University, Mymensingh, to test this fish effects in the presence of the bottom feeders either common carp (Cyprinus carpio) or mrigal (Cirrhinus cirrhosus) on production/reproduction of SIS, on the other fish species and on pond ecology. The data were analyzed using univariate and multivariate statistical techniques.