The separate and combined effects of copper and cadmium on the survivorship of penaeid shrimps

Critical survival tate for all larval stages of penaeid shrimp was determined using static bioassay with copper, cadmium and their 1:1 mixture. The lethal concentration (24 h LC50) was 200 mug/L of Cu, 250 mug/L of Cd and 300 mug/L of mixture in average for all larval stages along with slight variation at every stage (Nauplii - Myses III) in Penaous monodon LC50 was 400 mug/L, In Penaeus penicillatus LC50 the values were found to be 200 mg/L of Cu, 230 mug/L, of Cd and 250 mug/L for mixture in Nauplii to Myses however for postlarvae the LCH, was within the same as in Penaeus monodon; The estimation of survival rate within 24-48 h under lethal and acceptable concentration of copper and cadmium showed culturing farmers at most productive and safe condition of their ponds