ABSTRACT

Paraquat herbicides were tested on C. gariepinus fingerlings. Aquatic bioassays are essential for determining toxicant potency and concentration-dependent relationships. The goal was to determine paraquat's acute toxicity (Lc50) and sublethal influence on C.gariepinus mortality, behavior, and histopathology. The toxicity assessment for 60 fingerlings with a mean body weight of 3.155g and a length of 6.768cm showed 26.6% mortality, 73.33% survivability, 43.33% mortality, 56.57% survivability, 51.3% mortality, 48.33% survivability, and 78.3% mortality, 21.67% survivability for 3mg/l, 6mg/l, 9mg/l, and 12mg/l paraquat exposure. The 28-day sublethal toxicity showed 3.3% morality, 96.67 survivability at control, 1.6% mortality, 98.3% survivability, 16.67% mortality, 83.33% survivability, 23.33% mortality, 76.67% survivability, and 35% mortality, 65% survivability for 0.4mg/l, 0.6mg/l, 0.8mg/l, and 1.0mg/l on exposure. The Acute and Sublethal test demonstrates paraquat concentration increases death and decreases survival. The results also showed a stunning behavioral response such as loss of balance, erratic swimming, hanging on water column, lethargy, and discoloration of C. gariepinus fingerlings when induced with paraquat at acute toxicity 3mg/l, 6mg/l, 9mgl, 12mg/l and sublethal test 0.4mg/l, 0.6mgl, 0.8mg/l, and 1 Based on both results, the concentrated medium has more behavioral distortion. The findings emphasize the need to monitor and regulate paraquat and comparable herbicides to protect aquatic ecosystems and fish populations.