Icthyotoxic assessment of water extract from fresh Euphorbia heterophylla (L) plant stem to Barbus occidentalis (Pisces: Cyprinidae) (Boulencer, 1920) fingerlings

Abstract

Icthyotoxic assessment of water extract from fresh Euphorbia heterophylla (Limnaeus) plant stem on Barbus occidentalis (Boulenger, 1920) fingerlings was conducted using static bioassay tests over a period of 96 hours.  The range finding test was userd to determine the lethal concentration of the botanical on B. occidentalis and was found to induce varying behavioural response in the fish.  The 96h median lethal concentration (LC₅₀) of 2.42g/l and safety level of 0.24g/l were determined for B. occidentalis fingerlings exposed to water extract from fresh Euphorbia heterophylla (Linnaeus) plant stem.  A concentration dependent relationship was established for the effect of the toxicants on the test organisms.  Percentage survival of the test organisms followed a regular pattern increasing with decreasing concentration.  Prior to death of fish darkening of fish, erratic swimming and respiratory distress were observed.