Vol. 5 No. 1
Growth and yield of fish under high-density stocking and phased harvesting in rice-fish system.
Author(s): B.K. CHAKRABORTY AND M.J.A. MIRZA
Abstract: This study was carried out to enhance the productivity of rice-fish system following the management strategies like high-density initial stocking and phased harvesting, when the growth curve of carp and catfish starts to slow down. Impact of phased harvesting on overall growth performance of carp and catfish was reflected in faster growth of all species after 90 days of rearing, probably due to periodic phased harvesting that minimized the competition for food and space. Comparative lower apparent feed conversion ratio (1.78), higher survival rate 62.28±4.44 and higher fish yield (8.01±1.72 t/ha were also recorded in T1 (rice-fish culture with phased harvesting) than T2 (rice-fish culture without phased harvesting). The highest rice yield (7.6 t/ha) was recorded in T1 resulting from increased number of panicles per unit area as well as number of filled grains /panicle. Increase in rice yield over its monocrop (T3) was, higher in T1 followed by T2 because of improving soil fertility, recovering lost energy, adjusting energy flow by consuming plankton, weeds, insect and bacteria which used to compete with rice for nutrient. From economic point of view T1 also recorded better performance over other treatments. Treatment T4 was designed with only carp and cat fishes provided with a commercial fish feed, ‘Saudi-Bangla’ (32.10% crude protein) regularly. Overall performances indicated that this eco-friendly dual production system (rice and fish) and on-dyke horticulture technology generated a profitable return in a shortest possible time and helps in improving nutritional security, socio-economic status and employment opportunity.