Effect of Lethal Concentrations of Rubber Extract (Hevea brasiliensis) on the Survival on Fingerlings of Clarias gariepinus under Laboratory Condition.

Abstract

The water soluble fraction (WSF) of Hevea brasiliensis was tested against Clarias garienpinus, at 0, 30, 40, 50, 60 and 70mg/l in glass aquaria stocked with ten animals for 96 hours under observation for changes. Moribund swimming, restlessness, respiratory difficulties, depigmentation and mortalities were observed in the WSF exposure groups, but not in the controls. LC₅₀ values were estimated at 50.12mg/l. There was no significant difference in mortalities between the replicate group (P>0.05), leading to the conclusion that the WSF of Hevea brasiliensis had same toxic effects on both batches of the test organism.