Acute Toxicity of Niclosamide on Creeper Shell (Cerithidea cingulata) and Pacific White Shrimp (Litopenaeus vannamei) Postlarvae

Abstract

The efficacy of niclosamide for controlling creeper shell (Cerithidea cingulata) was studied. Static bioassay was used to determine the median lethal concentration of niclosamide needed to kill creeper shell within 96 hours (96-hr LC₅₀).  Water parameters were pH 7.0, 7.5, 8.0 and 8.5, with the 96-hr LC₅₀ at 0.22, 0.33, 0.34 and 0.48 ppm. Toxicity of niclosamide decreased when the pH increased. The 48-hr LC₅₀ of niclosamide on Pacific white shrimp (Litopenaeus vannamei) postlarvae 12 (PL12) was 1.36 ppm. The concentration of niclosamide at 1.0 ppm was more than two times higher than the concentration which caused 100% mortality of creeper shell in 96 hours, and had proven safe for PL 12. It is inferred from this experiment that niclosamide at 1.0 ppm can be used for water preparation, in order to eradicate creeper shell before stocking the PLs into the ponds.