Impacts of pesticide on the physico-chemical variables and zooplankton abundance of argulus sp. müller infected brood carp pond

Abstract

The study describes the impacts of organophosphate pesticide sumithion on physico-chemical variables and abundance of zooplankton of a commercial brood fish pond where the pesticide was used at monthly intervals to control the infection of Argulus sp. Compared to a control brood fish pond, notable differences were found in the monthly range of transparency, DO, free CO₂, hardness, ammonia nitrogen, nitrate-N and in monthly abundance of rotifers, nauplius, copepods, and  cladocerans of the treated pond. The monthly range of transparency, pH, DO, free CO₂, alkalinity, hardness and ammonia nitrogen  and nitrate-N varied from 15.5 to 29 cm, 7.5 to 9.5, 4.3 to 5.8 mg/l, 12.9 to 20.6 mg/l, 65 to 120 mg/l, 81 to 126 mg/l and 0.4 to 1.5 mg/l, 0.01 to 0.08, respectively in the treated pond, while in the control pond they varied from 22.1 to 30.1 cm, 7.2 to 8.5, 5.9 to 8.3 mg/l, 8.2 to 12.5 mg/l, 102 to 245 mg/l, 159 to 216 mg/l, 0.2 to 0.7 mg/l, 0.02 to 0.04 mg/l, respectively. The monthly abundance of rotifers, nauplius, copepods, cladocerans and ostracods varied from 425 to 1255 indiv/l, 10 to 100 indiv/l, 15 to 55 indiv/l, 5 to 40 indiv/l and 30 to 50 indiv/l in the treated pond, while they varied from 925 to 4320 indiv/l, 150 to 450 indiv/l, 50 to 260 indiv/l, 55 to 220 indiv/l and 20 to 200 mg/l in the control pond. The physico-chemical status and zooplankton abundance of the control pond indicate that the pesticide application considerably deteriorated the quality of water and decreased the zooplankton abundance of treated pond.