FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

The aim of this study is to investigate the median lethal concentrations (LC50s) of six practical chemotherapeutic agents on black carp Mylopharyngodon piceus under two ambient temperatures (20℃ and 30℃). The suitabilities of commonly recommended concentrations of agents are also examined for black carp. When the water temperature was 20℃, after 96 h of exposure, the LC50s of malachite green, methylene blue, copper sulfate, formalin, potassium permanganate, and masoten were 0.117, 35.542, 1.183, 85.058, 3.451, and 14.612 ppm, respectively. Furthermore, agents appeared stronger toxicities when the temperature was 30℃, and the LC50s were 0.114, 18.451, 0.976, 84.127, 3.105, and 7.226 ppm, respectively. The relative strength of agents is in the following order: malachite green, copper sulfate, potassium permanganate, masoten, methylene blue, and formalin. The results also showed that the commonly recommended concentrations of malachite green (0.15 ppm) and potassium permanganate (3-5 ppm) are not suitable to black carp for long-term exposure.
Key words：Black carp Mylopharyngodon piceus, Practical chemotherapeutic agents, Median lethal concentration