Acute toxicity of Lambda, Cyhalothrin Pyrethroid (Karate 2.5 EC) on the freshwater Catfish: Heterobrachus longifilis (Curvier and Valenciennes)

Abstract

Hetrobranchus longifilis fingerlings of mean weight 2.03±0.07 g and length 3.2±0.4cm were exposed to nominal concentration of lambda, cyhalothrin pyrethroid pesticide (Karate 2.5 EC) at 20 ppm, 40 ppm, 60 ppm, 80 ppm and 100 ppm through a gravimetric toxicant auto delivery system during a continuous flow through bioassay for 96 hours. The median lethal concentration 96-hr LC₅₀ value with lower and upper limits of toxicities were 31.62 ppm (14.79 ppm, 82 ppm) respectively. The threshold value was 14.75 ppm. Statistical analysis of the data showed a significant difference between the 96-hr LC_{50 values for the experimental fish at pKey Words: toxicity, lambada, cyhalothrin, pyrethroid, catfish, pesticide}