Determination of LC50 of Copper in Cirrhinus mrigala (Hamilton, 1822) and Ctenopharyngodon idella (Steindachner, 1866)

Abstract

Static bioassays were conducted on Cirrhinus mrigala
(8±0.5g) and Ctenopharyngodon idella (8.5±1g) fingerlings,
to determine the acute toxicity of copper. The
experiments were designed as three replicates
with five exposure groups arranged exponentially(
0.25, 0.75, 1.62, 3.25 and 6.62 mgl-1) for C.
mrigala and five concentrations (0.5, 0.75, 1.62, 2.5
and 3.25 mgl-1) for C. idella, besides the controls.
Each exposure group comprised of 10 fish each. The
median lethal concentration (96-h LC50) of copper
was determined as 0.74 mgl-1 Cu for C. mrigala and
3.07 mgl-1 Cu for C. idella respectively. Copper
proved to be more toxic to C. mrigala than C. idella.
The mortality rates increased with increasing copper
concentrations, in both species.