Journal of the Kalash Science, Volume-3, Number-2, 2015 : 11-17 ISSN 2321-7634 11 The impact of water quality on the population distribution pattern of cephalogonimid trematodes Cepahalogonimus yamunii in fresh water fish Heteropneustes fossilis at Allahabad, Uttar Pradesh Sushil K. Upadhyay 1 , Deepak Yadav 1 and Ravindra Kumar Pathak 2 1 Department of Zoology, Faculty of Science, Swami Vivekanand Subharti University, Meerut, U.P. 2 Regional Centre of Central Inland Fisheries Research Institute, Allahabad, U.P. Accepted: 27 October 2015 Abstract The impact of oscillations in water quality parameters on the population dynamics of the digenean trematodes of family cephalogonimidae Cepahalogonimus in fresh water fish Heteropneustes fossilis (Teleostomi: Heteropneustidae) from riparian wetlands of river Ganges at Allahabad was analyzed during the period of investigations (2014-2015). The augmentation in water temperature, alkalinity and lowering of dissolved oxygen (DO) concentration had positive influence on the flukes infection prevalence % and richness of parasites population. The significance of environmental parameters on the parasitic infection distribution patterns were calculated by modern biostatistical tools. The Eigen value of first component (PC1 p ) was found to be significant for dissolved oxygen in multifactorial analysis. The infection data supports the random distribution of trematodes in the host was observed on Poisson series (p>0.50). Keywords: Population dynamics, Cepahalogonimus yamunii, Riparian wetlands, Heteropneustes fossilis, Water quality. Introduction An organism has its identity as an individual and also as a component of population or community in specialized environmental conditions. The interactions of organism with their physical and biological environments are influencing their spatial and temporal distribution and abundance (Singh 1995, Ricklefs & Miller 2002, Singh & Kumar 2003). The parasites are known to drain resources upon their hosts, thereby forcing them to evolve abilities to counterbalance the hosts offensive stress responses. The echinostomatid parasitic infections by C. yamunii (Upadhyay et al. 2012) are encountered during the period of investigation within the fresh water host H. fossilis. The production of stress proteins in H. fossilis is associated with various environmental conditions and host-parasite stress interactions (Malhotra et al. 2009). The development and transmission dynamics of flukes in the aquatic and terrestrial food web is commonly taking place through the intermediate hosts or consumers. Therefore, the floral and faunal compositions of the surrounding environment are mainly responsible for the infestation and establishment of trematodes infection in the suitable hosts (Banerjee 1991, Chaurasia 2002, Jaiswal 2006). The climatic conditions and oscillations in the surrounding environmental factors and parameters are known to be creating an impact on the occurrence of helminthes infections in the hosts (Malhotra 1989, Hudson et al. 2006). The pattern of helminthes distribution dynamics and mean worm burden is remarkably conjoined with the level of causative agents responsible for high water pollution and fluctuations in physicochemical properties of surrounding environment of the host (Upadhyay 2012, Jaiswal et al. 2013, 2014). The Poisson distribution is an appropriate statistical tool to assess the affinity of the environmental influence on the parasite distribution within the host populations (Jaiswal et al. 2013, Upadhyay et al. 2013). The present investigation is a yesteryear study on the freshwater fish H. fossilis to make an attempt to correlate and validate the impact of changes in water quality on the cephalogonimid