Vol. 3, Issue 4 (2018)
Water quality impact in fish yield in different categories of carp ponds at eastern Terai region of Nepal
Author(s): Umita Sah, Yuktilal Mukhiya, Suresh K Wagle
Abstract: The quality of water is changing in response to daily, seasonal, climatic rhythms and characteristics of the surrounding environment of fish ponds. Water retention duration, man-made intervention and characteristics of pond bottom also affect the water quality and fish productivity in different ponds. This study was designed to assess the water quality of different types of ponds and their impact on fish productivity. Water quality of four different types of ponds viz. perennial, drainable, seasonal and new ponds in eastern Terai of Nepal was monitored and fish yield was recorded during November to December 2015 to establish correlation among pond types, water quality and fish productivity. The water samples were analysed for various physico-chemical characteristics like temperature, DO, pH, turbidity, total dissolved solids (TDS), total suspended solids (TSS), phosphate, ammonium, total nitrogen (TN), acidity, BOD, COD, CO2, total alkalinity (TA) and total hardness (TH). The ranges obtained for the parameters DO (5.1-5.6 mg/L), pH (7.9-8.6), TDS (127.6-225.6 mg/L), TSS (54.6-80 mg/L), phosphate (0.06-0.4 mg/L), ammonium (0.77-1.19 mg/L), TN (5.4-7.3 mg/L), acidity (5-15 mg/L), BOD (12.6-35.6 mg/L), COD (26.6-66.6 mg/L) and CO2 (8.8-14.6 mg/L) were not significantly different (p>0.05) among pond types. The ranges obtained for temperature (19.7-21.6 oC), turbidity (34.8-236 NTU), TA (90.3-186.9 mg/L) and TH (82.6-173.3 mg/L) were significantly different (p<0.05) among pond types. Carps fish yield was significantly low (p<0.05) in new pond (1.17 t/ha) compared to other types of pond. The fish yield obtained from perennial (4.5 t/ha), drainable (3.5 t/ha) and seepage (3.0 t/ha) ponds was not significantly different (p>0.05). Water turbidity, TA and TH had the significant correlation (p<0.05) with fish yield irrespective of pond types. This study will aid fish farmers on the necessary treatment needed to effectively use water for carp fish farming in different types of pond.