Hindawi Publishing Corporation ISRN Zoology Volume 2013, Article ID 492613, 7 pages http://dx.doi.org/10.1155/2013/492613 Research Article Haematological Response of African Catfish (Clarias gariepinus Burchell 1822) Fingerlings Exposed to Different Concentrations of Tobacco (Nicotiana tobaccum) Leaf Dust Safina M. Musa, 1 Christopher Mulanda Aura, 2,3 Erick Ochieng Ogello, 1 Reuben Omondi, 4 Harrison Charo-Karisa, 5 and Jonathan Mbonge Munguti 5 1 Kegati Aquaculture Research Station, Kenya Marine and Fisheries Research Institute, P.O. Box 3259-40200, Kisii, Kenya 2 Kenya Marine and Fisheries Research Institute, P.O. Box 81651-80100, Mombasa, Kenya 3 Laboratory of Marine Bioresource & Environment Sensing, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido 041-8611, Japan 4 Kenya Marine and Fisheries Research Institute, P.O. Box 1881-40100, Kisumu, Kenya 5 National Aquaculture Research Development & Training Center (NARDTC)-Sagana, Kenya Marine and Fisheries Research Institute, P.O. Box 26-10230, Sagana, Kenya Correspondence should be addressed to Safina M. Musa; safeenamusa@yahoo.com Received 15 July 2013; Accepted 17 August 2013 Academic Editors: I. Krams, T. Miyata, and D. Park Copyright © 2013 Safina M. Musa et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. e present study set out to investigate the haematological effects of tobacco leaf dust on African catfish, Clarias gariepinus, fingerlings, with a mean weight of 3.01 ± 1.25 g using “static renewal bioassay system” during a 120-hour bioassay exposure period. Water quality parameters such as pH and dissolved oxygen significantly decreased while total alkalinity and conductivity increased significantly in the exposed media, compared to the control test. Leucocytes counts increased significantly while erythrocytes counts decreased significantly with increasing concentration of tobacco dust. Packed cell volume significantly reduced with increase in the concentration of tobacco dust. Haematological examination showed that there was destruction of the erythrocytes production, and the concentration of haemoglobin was much lower in the exposed fish compared to the control depicting an anaemic condition. e results could provide baseline information for the safe limits of using tobacco leaf dust in fish ponds; hence 1.56 g L −1 concentration of tobacco leaf dust was recommended for pond preparation for Clarias gariepinus fingerling stocking. For better survival rates, the fish should only be introduced in the pond aſter three days of tobacco application. 1. Introduction African catfish (Clarias gariepinus) is one of the most important fish species currently being cultured both inside and outside its natural range of tropical and subtropical environments [1, 2]. Positive attributes such as resistance to diseases, high fecundity, and ease of larval production in captivity make it of commercial importance in aquaculture [3–5]. However, the main constraint facing the culture of C. gariepinus is the low survival during the larval and fingerling stages [6] leading to insufficient amounts of quality catfish seed. High mortality rates occur among larval stages of catfish, some of which are attributed to infectious diseases caused by parasites [7]. Parasitic pathogens infecting cultured fish are well known to cause mortality and significant losses both in culture and capture fisheries [8, 9]. It is therefore apparent that management protocols that limit mortality and enhance fingerling growth should be clearly described to ensure improved survival and sufficient supply of catfish fingerlings. Fish farmers oſten use tobacco leaf in controlling unwanted organisms and pests [10, 11]. e attraction of tobacco leaf dust as a biocide according to Aleem [12] is because of its inexpensiveness, local availability, and easy degradability. According to Ogello et al. [13], tobacco con- centrations of 1.75 g L −1 and 2.0 g L −1 had high hazard ratios and low survival rates and were the most effective in the eradication of M. tuberculatus and are the recommended