Acute toxicity of gramoxone (paraquat-dichloride) to the fresh water catfish <i>Clarias gariepinus</i> (burch) post fingerlings.

Abstract

Clarias gariepinus post fingerlings ranging from 3.0 to 4.12g +- 0.06 S.E were subjected to 20ppm, 40ppm, 60ppm, 80ppm and 100ppm of gramoxone for 96 hours static bioassay. The median lethal concentration (LC50) value of gramoxone for Clarias gariepinus post fingerlings was 44.67ppm and a safe concentration of 4.47ppm. The fish species showed several abnormal behaviour which included restlessness, arena movements, loss of equilibrium, strong spasm, paralysis and sudden quick movement during the exposure. The effect of the treatment on some blood parameters analysed showed decrease in haemoglobin value (6.9 to 6.0g), haematocrit value (26.16 to 6%), red blood cell count (6.7 x 10-5mm3 to 1.3 x 10-5 mm³), white blood cell count (6.7 to 2.0 mm³ ), increase in mean corpuscular haemoglobin (32.56 to 33.62%). Gramoxone treated groups also showed significant increase in mean corpuscular volume (P>0.05) and later decreased at the highest concentration of the pesticide (31.53 to 58.08 to 30. 4um3). The cause of alteration in blood parameters is discussed.

Keywords: Acute, Toxicity, Gramoxone, Freshwater Catfish, Haematological parameters, Post fingerling

Nigerian Journal of Fisheries Vol. 4 (2) 2007: pp. 105-113