اثر فلزات سنگين مس و سرب بر روي بقاء، رفتار و رشد ماهي سفيد (Rutilus frisii kutum)

Effect of heavy metals (copper and lead) on survival, behavior and growth performance of Caspian Sea kutum (Rutilus frisii kutum

The aim of present study was to determine the LC50 value of copper and lead and effect on behavior and gill texture in Caspian Sea kutum. First For determination of the LC50 (lethal concentration) values، Following a range finding test، eight Cu (0.5، 0.75، 1، 1.5، 2، 2.5، 3 and 3.5 mg/L) and Pb (100، 200، 220، 240، 260، 280، 300 and 320 mg/L) concentrations were chosen for Caspian Sea kutum. For each metal-treated and Control tree replications were conducted. The results indicated that median lethal concentration (LC50) of copper to Caspian sea kutum (Rutilus frisii kutum) for 24، 48، 72 and 96 h of exposure are 2.944، 2.756، 2.562 ppm and 2.310 ppm respectively and median lethal concentration (LC50) of lead to Caspian sea kutum (Rutilus frisii kutum) for 24، 48، 72 and 96 h of exposure as 315.841 ppm، 298.456 ppm، 281.419 ppm and 268.065 ppm respectively. LC50 increased with decrease in mean exposure times for both metals. The behavior of fish remarkably changed due to the treatment of lead and copper when compared to the control. The various locomotary responses exhibited by fish due to sub lethal concentrations of lead and copper during initial stage of exposure included restlessness، erratic and fast swimming، abrupt change in position and direction، jumping and overall hyperactivity were noticed. The fish showed surfacing tendency throughout the experimental period. Thereafter experiment for determine the growth performance fish were kept in the aquaria containing sub-lethal concentrations of copper sulfate (0.11 and 0.23 mg L-1) and lead nitrate (13.4 and 26.8 mgL-1) grown for 60 days، while control fish were placed in metal free water. The chronic sub-lethal water-borne Cu and Pb exposure to the fish exerted that larvae had significantly decreased final body weight in comparison to control treatment. The Cu and Pb also had significant negative effects on specific growth rate (SGR). Hence، concluded that copper is more toxic than lead for Caspian Sea kutum (Rutilus frisii kutum).