48 Asian Fisheries Science 32 (2019):48–55 Asian Fisheries Science 32 (2019):48–55 48 Comparative Toxicological Effects of the Herbicide, Atrazine, on Fingerlings and Juveniles of African Catfish, Clarias gariepinus (Burchell, 1822) ©Asian Fisheries Society ISSN: 0116-6514 E-ISSN: 2073-3720 https:// doi.org/10.33997/j.afs.2019.32.02.001 V.F. DOHERTY * , ANEYO IDOWU, ABDULLAHI ADEOLA, OLUWATOBI OWOLABI Yaba College of Technology, Yaba, Lagos 01234, Nigeria * E-mail: funmilayodoherty@yahoo.co.uk | Received: 11/03/2019; Accepted: 20/05/2019 Abstract This research was aimed at evaluating the toxic effects of atrazine, a commonly used herbicide on acetylcholinesterase (ACHE) activity, lipid peroxidation and testosterone levels in different growth stages of African catfish, Clarias gariepinus (Burchell, 1822). The acute and the chronic evaluations were conducted while activities of acetylcholinesterase, lipid peroxidation and testosterone levels were determined using predetermined sub-lethal concentrations of the herbicide. The mean 96-h lethal concentration (LC50) of atrazine exposed to catfish fingerlings and juveniles were 0.350 mg·L -1 and 0.553 mg.L -1 , respectively. Acetylcholinesterase activity was higher in the brain of juveniles (25.0 µmol.mL -1 ) exposed to the herbicide than that of the fingerlings (17.0 µmol.mL -1 ), and a similar pattern was observed in the liver. Malondialdehyde was higher in the fingerlings (liver and brain) (2.7 and 2.0 µmol.mL -1 ) exposed to the herbicide than the juveniles (1.8 µmol.mL -1 and 1.6 µmol.mL -1 ). Testosterone was not detected in the serum of fingerlings exposed to atrazine herbicide. The results of this study elucidated potential biomarkers for monitoring fish health in rivers receiving runoffs of the herbicide, atrazine, and the risk of loss of fisheries productivity attributable to the anti-androgenic properties of the herbicide. Keywords: farm runoffs, agrochemicals, lipid peroxidation, acetylcholinesterase, endocrine disruption Introduction As developing countries strive for self-sufficiency in agriculture, it is expected that the use of agrochemicals such as herbicides will also increase as farmers try to optimise productivity per hectare of land. Agrochemicals pose a considerable threat to aquatic life due to runoffs which enter into nearby lakes, rivers and streams. Atrazine is commonly used as agrochemicals and it has the capacity to be transported through long distance, as a result their residues have been detected in food and households (Mahmood et al. 2016). The cause of toxicity they pose to aquatic and other non-target fauna cannot be excluded from over application and poor agro- extension services to educate farmers. Atrazines are classified under the group of herbicides known as the S-triazine group, and they are important water contaminants which pollute various water bodies, including marine and freshwater (Tasli et al. 2009). Its mechanism of activity in weeds and other plants has been reported to include disruption of biological structures and processes, or the promotion of uncontrolled growth and inhibition of photosynthesis (William et al. 2008; Dodge et al. 2010; Giddings et al. 2011). Atrazine can remain in water bodies over long periods, especially in bodies of water with high pH. Several reports have paid attention to the route of entry of atrazine in water (Wauchope 1978; Ren et al. 2002). Atrazine is known to be an endocrine disruptor which is potent at environmentally low levels, and it has been shown to affect the larval development process of amphibians in a study conducted by Hayes et al. (2010). Atrazine alters biochemical and physiological processes and enzymatic activities of fish in polluted waters containing different levels of the herbicide (dos Santos and Martinez 2014).