109 Pakistan Veterinary Journal ISSN: 0253-8318 (PRINT), 2074-7764 (ONLINE) Accessible at: www.pvj.com.pk The Effect of Fish Size and Condition on the Contents of Twelve Essential and Non Essential Elements in Aristichthys nobilis M. Naeem*, A. Salam, S. S. Tahir 1 and N. Rauf 1 Institute of Pure and Applied Biology, Bahauddin Zakariya University, Multan 60800; 1 Central Laboratory for Environmental Analysis, Pakistan Environmental Protection Agency, Islamabad, Pakistan *Corresponding author: dr_naeembzu@yahoo.com ARTICLE HISTORY ABSTRACT Received: Revised: Accepted: November 29, 2010 January 03, 2011 January 07, 2011 Key words: Aristichthys nobilis Metal Composition Fish size Condition factor Predictive equation The correlation coefficients between fish size (body weight and total length) and metal contents (Na, K, Ca, Mg, Mn, Fe, Cu, Zn, Cr, Co, Cd and Pb) in whole fish (Aristichthys nobilis) were determined. A total of 71 fish samples were collected from hatcheries and fish reservoirs located in Islamabad and Fatehjung. Highly significant (P<0.001) relationship between metal concentrations and fish size was found. Most of the metals (Na, K, Ca, Mg, Cu, Zn, Cr, Cd and Pb) showed an isometric increase, while Mn, Fe and Co showed an allometric increase in with increasing body weight. All metals showed isometric increase, while, Na, Mn, Fe, Cu, and Co showed positive allometric growth in relation to total length. The correlation coefficient (r) between different variables and wet body weight, condition factor was found highly significant (P<0.001) in examined fish except for Na, Ca, Cu, Zn, Cd and Pb while for total length the same results found except Ca, Cd, Zn and Pb. Variance inflation factor values of regression coefficients in multiple regression analysis for each variable were lesser than 10. The metal levels of the examined fish were lower than the recommended values in fish and fishery products set by FAO. ©2011 PVJ. All rights reserved To Cite This Article: Naeem M, A Salam, SS Tahir and N Rauf, 2011. The effect of fish size and condition on the contents of twelve essential and non essential elements in Aristichthys nobilis from Pakistan. Pak Vet J, 31(2): 109- 112. INTRODUCTION In aquatic environment, fish reflects the effects of numerous interacting biotic and abiotic factors. Mostly the variation in elemental concentration in fish tissue has been attributed to variation in size and age (Phillips, 1980). Many studies have focused attention on the dependence between the contents of metals and the size (weight and length) of these fish (Kroupa and Hartvich, 1990; Falandysz, 1994; Kostecki, 2000). Variation of elemental concentration in fish tissue due to size has been reported (Salam et al., 2002; Canli and Atli, 2002; Farkas et al., 2003; Luczynska and Tonska, 2006; Promya and Chitmanat, 2011). Jezierska and Witeska (2001) reported that smaller younger fish accumulate more metal (except mercury) than larger, older fish, which may stem from the higher metabolic rate. There are many other factors which influence elemental concentration levels in fish. These include seasonal differences in fish metabolic rate which determines the physiological condition of fish (Kargin, 1996; Farkas et al., 2002; Ashraf et al., 2011). Variation in elemental concentration depending on condition of fish is due to relative dilution effect of lipid content of tissues (Farkas et al., 2002). According to Farkas et al. (2003), concentration of trace metals in fish is influenced in a remarkable degree by the physiological condition of organisms. This is an important for comparative bio- monitoring studies. The concentrations themselves are the result of uptake and release processes, with elements characteristic kinetics and their biological half time (Von Burg and Greenwood, 1991). It helps to study the environmental dependent variation in the levels of toxic metals found in culture-able fish and to initiate correlation studies related to percent trace metals level in whole body of fish in relation to body size and condition factor. It also generates a realistic picture of the bioaccumulation pattern of the metals in this species. This study investigates relationship of fish size and nutritional quality, occurrence of trace metals and further identifies the optimum size, i.e. total length and body weight, of this species suitable for human consumption. RESEARCH ARTICLE