An assessment of physico-chemical water quality parameters in earthen fish ponds

Abstract

Aquaculture is one of the fastest food growing industries in the world with potential to supplement the ever declining capture fisheries stock. Nevertheless, one of the major challenges limiting fish productivity in earthen ponds is the unreliable water quality, which is either attributed to point or non-point pollution from human activities or in-pond activities including over feeding and poor pond maintenance. Therefore, this study aimed to assess the physico-chemical water quality parameters in earthen ponds. The specific objectives were to: i) find out the physio-chemical water quality composition of earthen fish ponds in relation to temperature, pH, dissolved oxygen (DO) concentration, electrical conductivity (EC),total dissolved solids (TDS) and total suspended solids (TSS); ii) determine if named parameters in objective 1 are within the recommended standards to support fish culture, and iii) suggest the management practices for improved and sustained water quality of earthen ponds. This study was conducted in Kamuli district, Kisozi sub-county, and this involved random selection of 5 fish ponds based on accessibility. The fish ponds were monitored over a period of six (6) weeks from May-June, 2024. The physico-chemical water quality parameters monitored included: Temperature, DO, pH, EC and TDS were measured in-situ using Multimeter parameter probe(HANNA H198194) while TSS was analysed in the laboratory following standard methods of water and wastewater treatment by APHA (1998).

Results for the physio-chemical water quality composition in five earthen fish ponds that is to say A, B C, D, and E was: Temperature 26.06±1.44, 25.58±1.40, 25.30±1.41, 25.47±1.22 and 26.83±2.59 respectively; DO: 5.30±0.66, 5.41±0.66, 5.35±0.62, 5.72±0.41 and 4.91±0.71, PH was 7.51±0.16, 6.74±1.28, 7.09±0.11, 6.33±0.30 and 7.31±0.29 respectively. EC was found to be 349.72±10.73, 346.88±22.23, 662.44±13.15, 98.83±19.67 and 280.66±23.11 for ponds A, B, C, D and E respectively. TDS: 174.11±4.54, 172.55±1.48, 331.66±6.58, 48.83±9.07 and 143±11.08 and TSS water was 166.67±98.47, 141.67±66.85, 200±95.34, 200±95.34 and 141±66.85 respectively, and were found to be within the recommended ranges required to support fish culture except TSS. It is recommended that pond management should be encouraged through regular water exchange, influent treatment and controlled feeding to maintain TSS levels within recommended standards.