Acute Toxicity of Water Soluble Fractions of Crude Oil to the Nile Tilapia, Oreochromis niloticus (L.) E. Omoregie Fisheries Research Unit, Department of Zoology, University of Jos, P.M.B. 2084, Jos, Nigeria Received: 25 July 2001/Accepted: 20 December 2001 Bull. Environ. Contam. Toxicol. (2002) 68:623– 629 © 2002 Springer-Verlag New York Inc. DOI: 10.1007/s00128-001-0300-y Bulletin of Environmental Contamination and Toxicology 623