| Abstract: |
Environmental pollution with pesticides is one of the most deleterious effect to the biological life, survival, metabolism and distribution of fish in the aquatic environment.A group of apparently healthy Clarias lazera fish were exposed topesticides (sumi-alfa Pyrethoid Insecticide, SumithionOrganophosphorus Insecticide and Saturn thiocarbamate Herbicide) to determine (1000/0 and 50% mortalities) and the effect of short term exposure half lethal concentration dose (LC50 up to 96 hrs.) and the long tenn exposure (111 0 & 1120 LC50) of each pesdays, of acute exposure and 15, 30, 45, 60, 75 and 90 days of exposure toeach pesticides. Clarias lazera exposed to LC50 pesticides showed hyper excitability, uncontrolled muscular tremors, loss of equilibrium, severe nervous and respiratory manifestation, excessive mucus secretion, withhemorrhagic skin. Clarias lazera exposed to (1110 & 1120) LC50pesticides showed loss of reflex action, off food, gasping, nervousmanifestation, excessive mucus production, darkening andhemorrhagic ulcer formation on the skin. Peticheal hemorrhages incaudal area and fin, abdominal distensiqn with ascities and edema wereseen. Macroscopically, the Clarias lazera exposed to LC50 showedsevere congestion and excessive mucus secretion with hemorrhages ingills, while all parynchymatous organs showed mild ascities wereseen,and the brain was congested and hemorrhagic. While in chronic
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