Assessment of Physico-Chemical Parameters under Different Management Practices of Prawn Farms

Abstract

This thesis deals with the study of identification of different physico-chemical and biological parameters in mono and integrated culture of prawn ponds. The experiment was conducted in the villages of Solua and Ramkrishnapur, Dumuria Upazila, Khulna district, south-west region of Bangladesh. Eight ponds were selected for the experiment of which four were under monoculture and the rest four were under integrated culture of fresh water prawn. Pond sizes were between 1.0 and 2.5 ha. The study was conducted during the period of July to October, 2012. In-situ measurement and sample collections were done at 15 days interval. Various water quality parameters eg temperature, DO, pH, alkalinity, ammonia, nitrite, salinity, transparency, acidity, hardness and total phosphorus which are thought to have significant impact on the growth of M. rosenbergii were measured during the study period. The water temperature was found to vary between 29 to 33 °C in mono culture system while in integrated culture it was between 30 to 32 °C. The pH of the water was slightly alkaline (5 to 8 both in monoculture and integrated culture). Water salinity varied from 0 to 6 ppt in mono culture and 0 to 5 ppt in integrated culture. The values of DO, alkalinity, ammonia, nitrite, transparency, acidity, hardness, total phosphorus and chlorophyll were found to vary between 4.7 to 5.8 mg/l, 115 to 169 mg/l, 0 to 0.066 mg/l, 0 to 0.03 mg/l, 20 to 28 cm, 75 to 90 mg/l, 29 to 45 mg/l, 0.14 to 0.52 mg/l, 0 to 0.005 mg/l respectively, in prawn monoculture system, while in integrated culture system the values varied between 100 to 168 mg/l, 0 to 0.02 mg/l, 0 to 0.231 mg/l, 18 to 28 cm, 60 to 88 mg/l, 22 to 33 mg/l, 0.15 to 0.9 mg/l, 0.001 to 0.02 mg/l respectively. No significant variations in water quality parameters were noticed between the two culture systems however a little variation in one parameter influenced the other factor during the culture period.