Pakistan J. Zool., vol. 45(6), pp. 1727-1734, 2013. Fresh Records on Water Quality and Ichthyodiversity of River Swat at Charsadda, Khyber Pakhtunkhwa Ali Muhammad Yousafzai, 1 * Wisal Khan 1 and Zaigham Hasan 2 1 Department of Zoology, Islamia College University, Peshawar 2 Department of Zoology, University of Peshawar, Peshawar Abstract.- A study on the fish fauna and water quality parameters of River Swat at Charsadda, Khyber Pakhtunkhwa, Pakistan was conducted, with an aim to determine fresh records of water quality variables and fish fauna after heavy floods of July, 2010 in the province. For fish distribution a 35 km belt of the river was explored for four months and every effort was made to collect the fish specimen by any legal mean. During this study the mean values recorded for physico- chemical parameters were water temperature 19.8°C, pH 7.6, dissolved oxygen 9.65 mg/l, electrical conductivity 199.47 µS/cm, TDS 127.66 mg/l, TSS 93.78 mg/l, total hardness 118.75 mg/l, calcium hardness 75 mg/l, magnesium hardness 43.75 mg/l, sodium 5.325 mg/l, potassium 3.175 mg/l, total alkalinity 97 mg/l, chloride 15.3 mg/l and nitrite 0.0092 mg/l. All these values were within the limits prescribed by the standard methods for the examination of water, sewage and industrial wastes. In the present study a total of 38 fish species belonging to; 6 orders, 9 families and 24 genera were recorded. Cyprinidae was the richest family and was represented by 20 species, Nemacheilidae by 4, Sisoridae by 6, Channidae and Schilbidae by 2, Mastacembelidae, Schilbidae, Belonidae and Chandidae by single species. Results report six (6) species missing in the present study in comparison with the past records. Key words: Fish fauna, Cyprinidae, Channidae. INTRODUCTION The River Swat is one of the main rivers flowing in Khyber-Pakhtunkhwa (Fig. 1). It passes through the entire District Swat and enters District Dir at Chakdara. It joins River Panjkora at lower Dir and then passes through Malakand, Charsadda and finally enters the River Kabul at Nissata. Topographically the River Swat flows down the altitude at a faster speed through a series of hills. The River is wider at one place and narrows at another. The River is fed by glaciers and snow and has a great volume in summer. Down in the plains it passes through thickly populated towns and agricultural fields irrigating large areas of District Swat and District Charsadda. Different species or age classes of same specie vary considerably in vulnerability to flooding (Harrell, 1978). Juvenile life stages are particularly susceptible to heavy losses during extreme floods in high-gradient systems (Elwood and Waters, 1969). Suspended sediment loads due to flooding can result ____________________________ * Corresponding author: alifishzoology@yahoo.com 0030-9923/2013/0006-1727 $ 8.00/0 Copyright 2013 Zoological Society of Pakistan in increased water column respiration, decreasing dissolved oxygen concentrations (Roozen et al., 2003). Large numbers of young fish are even lost during average seasonal flooding in systems where the timing of high flows coincides with fragile life stages (Nehring and Miller, 1987). Very young fishes may be particularly vulnerable to floods because of their poor swimming ability and small size (Harvey, 1987). Floods cause a sudden dramatic change in all environmental parameters and all these changes influence the organisms inhabiting the reservoir ecosystem from microorganisms to fish (Godlewska et al., 2003). Floods can alter both assemblage structure and abundance of fishes in stream reaches (Ross et al., 1985). Floods which occur over much shorter periods of time than drought can alter stream channel morphology, kill or displace biota downstream (Harrell, 1978). Flood causes major disturbances to stream ecosystems that kill or displace organisms and modify habitats (Franssen et al., 2006). The large input of organic matter to aquatic flood plain habitats may reduce dissolved oxygen and result in the emigration or death of a great number of fishes (Winemiller, 1989). Summer floods are detrimental to cyprinids and catostomids