Preliminary Observations on the Effects of Lime and Common Salt as Prophylactics and Therapeutics Against Epizootic Ulcerative Syndrome in Fish Culture Ponds

Abstract

To control epizootic ulcerative syndrome (EUS) in fish, pond treatment using quick lime (CaO) combined with common salt (NaC1) was tested in seven experimental ponds at Gazipur and Faridpur, Bangladesh. Basic water quality parameters were monitored before and during treatments. Therapeutic treatments using lime (CaO) either at 0.005 or 0.01 ppm or lime plus common salt at 0.005 ppm each gave unsatisfactory or delayed results. Simultaneous treatments using both chemicals at 0.01 ppm each improved water quality parameters (pH, acidity, alkalinity, hardness and chloride), and led to healing of lesions of affected fishes after fifteen days of application. The same dosages used as prophylactics were applied as field trials just before the predicted outbreak and no fish with lesion was observed. Follow up field trials in two subsequent seasons have also indicated the effectiveness of the present doses and treatments. These techniques are disseminated as adaptive measures through government extension agents and are being practiced in semi-intensive fish culture ponds in Bangladesh to combat EUS.