Effects of Chlorpyrifos Exposure on Growth and Food Utilization in Australian Catfish, Tandanus tandanus

Australian catfish, T. tandanus were exposed to a short term pulse of chlorpyrifos at 2 or 10 mu g L-1 and grown in optimal conditions to investigate the effect of the pesticide on fish growth. The final weight was lower in fish exposed to chlorpyrifos (8.54 +/- 0.19 and 8.77 +/- 0.44 g) respectively compared to the control fish (10.5 +/- 0.72 g) while the hepatosomatic index in fish exposed to chlorpyrifos was a higher (1.86 +/- 0.10 and 2.01 +/- 0.12) than in the control fish (1.65 +/- 0.14). Both bi-weekly growth rate and brain Acetylcholinesterase (AChE) activity increased with post-exposure time.