Acute toxicity of Calcium chloride on different stages (egg, spawn, fry and fingerling) of rohu (Labeo rohita Hamilton)

摘要

The acute toxicity of calcium chloride (CaCl2) was studied on the early stages of Indian major carp rohu, Labeo rohita (egg, spawn, fry and fingerling) through bioassay tests. Percentage of dead or damaged egg, spawn, fry and fingerling at 6, 12, 18, 24, 36, 48, 60, 72 and 96 hours were recorded for the calculation of LC50. The increase in CaCl2 concentration in water increased the toxicity and reduced the duration to damage 50% of the eggs, spawn, fry and fingerling. Low hatchability, delayed hatching, poor survival observed in the test solutions >1000ppm concentration. The deformed and dead larvae were observed through microscopic examinations. The behavioural studies such as swimming, surfacing, activeness and survival were also observed in spawn, fry and fingerling. The LC50 values of CaCl2 for egg, spawn, fry and fingerling were 3743.79-28.93ppm, 7249.78-1260.73ppm, 9872.44-6384.12ppm and 12276.52-9987.67ppm in 6 - 96 hours respectively.