Abstract
Two sets of experiment each with three replications were conducted at the Freshwater Station, Fisheries Research Institute, Mymensingh during the period from June, 1990 to June, 1992 to study the water quality inter- relationships and their impact on production of fish in integrated duck-cum- fish farming system. The two treatments tested in the first year were FYT1: silver carp 30%, grass carp 10%, catla 10%, rohu 25% and mrigal 25% at the rate of 600 fingerlings/pond or 7500/ha; and FYTI: silver carp 10%, grass carp 5%, catla 10%, rohu 25%, mrigal 25% and tilapia 25% at the same rate as FYT, while those of the two treatments in second year were SYT: silver carp 11.43%, grass carp 5.71%, mirror carp 5.71%, catla 5.71%, rohu 14.29%, mrigal 14.29% and rajpunti 42.86% at the rate of 700 fingerlings/pond or 8750/ha; and SYTII: : rajpunti 29.41%, red tilapia 58.82% and African magur 11.77% at the rate of 1700 fingerlings/pond or 21250/ha). 90-day-old 50 female Khaki Campbell ducklings per pond (625/ha) in the first year and 60-day-old 30 ducklings per pond (375/ha) in the second year were raised in the sheds constructed over ponds each of 0.08 ha area. The ducks were fed with a common standard poultry ration containing 89% dry matter (DM), 2.8% total nitrogen (N), 1.2% available phosphorus (P), 0.7% potassium (K), 2.19% calcium (Ca), 35.23% organic carbon (OC) and 2701 metabolizable energy (ME kcal/kg). The excreta produced by the ducks were collected and analysed. Excreta consisted of 1.58% N, 0.84% P, 0.56% K, 1.80% Ca and 18.07% OC. Duck utilized higher proportion of DM and Ca only, but higher proportion of N,P,K and OC were voided into the ponds.
Water quality parameters such as water temperature, depth, transparency, dissolved oxygen (DO), free carbon-di-oxide (CO2), pH, total alkalinity, total hardness, phosphate-phosphorus (PO-P), ammonia-nitrogen (NH-N), nitrite- nitrogen (NO,-N), nitrate-nitrogen (NO,-N), biochemical oxygen demand (BOD).