FISH ECOLOGICAL STUDIES AND ITS APPLICATION IN ASSESSING ECOLOGICAL INTEGRITY OF RIVERS IN NEPAL By Bibhuti Ranjan Jha Thesis Submitted in partial fulfillment of the requirement for the degree of Doctor of Philosophy in The Department of Biological Sciences and Environmental Science School of Science Kathmandu University Dhulikhel, Nepal January 2006 FISH ECOLOGICAL STUDIES AND ITS APPLICATION IN ASSESSING ECOLOGICAL INTEGRITY OF RIVERS IN NEPAL By Bibhuti Ranjan Jha Supervisors: Dr. Herwig Waidbacher & Dr. Subodh Sharma Ao. Univ. Professor Associate Professor Universität für Bodenkultur (BOKU) Kathmandu University (KU) Vienna, Austria Dhulikhel, Nepal Kathmandu University January 2006 ACKNOWLEDGEMENT Writing thesis for me was indeed a long journey covering two continents Asia and Europe and spanning almost three years. However, it was the first time I realized that I was surrounded by wonderful people and institutions. Let me start with my two supervisors, Prof. Dr. Herwig Waidbacher, Head of the Department of Water Atmosphere and Environment, BOKU and Dr. Subodh Sharma, Department of Environmental Science and Engineering, KU both of whom have given me all the support, guidance and confidence to carry out this work. I would like to express my sincere gratitude and honor to them. It was so nice to feel that I had a similar level of easiness in approaching Dr. Rana Bahadur Chhetri, then Head of the Department of Biological and Environmental Sciences, KU and now Associate Dean, and Prof. Dr. Mathias Jungwirth, Head of the Institute of Hydrobiology, BOKU. I found both of them full of virtues. I am also grateful to KU for providing all kinds of support including the equipment and logistics to complete this work. The Dean of School of Science, Prof. Dr. Pushpa Raj Adhikari was particularly after me to push into this work. Thank you so much sir. Dr. Sanjay N. Khanal, my department head at KU not only gave me the tips on academic matter but also on the life in Vienna. In addition I sincerely acknowledge the encouragement and moral support received from the entire KU family. I am sure my colleague in the department and other friends in KU are just waiting for me to host a party. BOKU family, especially the members at the institute were equally inspiring. Prof. Moog, Prof. Muhar and Prof. Schmutz were always friendly and ready to help in every matter. I also remember the warm friendliness of benthos group upstairs and fish group downstairs. The guys with whom I was working together in Keller are just amazing. Gü, Manu, Frangez, Wiesel, Ande, Andreas, Thomas, Patrick, Gonzalo, Doris, Nicole, Catherine, Helmut, Philipp and Jonathan were all wonderful friends and never allowed my spirit go down. The songs of Berthold will always ring in my ears. All of you will remain in my memory forever. Franziska, the coordinator of the institute is a super lady. Not only she was helping me in all office and domestic matters but also provided me motherly advices whenever we met. Christian Dorninger is another person who has been seen always in helping mood. I feel proud to name my sampling team members who helped me during the field trips. Sujan, Arbinda, Shekhar, Bibhuti, Amul, Paras, Anil, Sushil, Amir, Keshab, Khadak, Paras, Sujeet, Swastik, Diwas and Ramesh! I love you all. Pancha and Shiva, who also work in the laboratory, were also integral part of the sampling team. Among colleagues Subhash, Bed, Manoj and Dr. Sanjaya were always with me one time or another. Among the institution, I always find the central department of Zoology of Tribhuvan University very homely, may be because I used to be a student there. Prof. Dr. Jiwan Shrestha particularly, provided me with unselfish help in identifying the sample. I would like to express my heartfelt thanks to you, madam. Thanks also to Dr. Mana Wagley, who helped me in developing the objectives of the study. Dharani Man Singh is not only my close neighbor but was also closely watching my progress during field studies. Many times I made use of his good office, Department of Fisheries, Balaju for literature and taxonomy of fish. There I also got the opportunity to talk with Dr. Swar and took some help from Ramola madam. Sincere thanks to all of you. I would also like to acknowledge the cooperation of Department of National Parks and Wildlife Conservation (DNPWC), Royal Chitwan National Park, Shivapuri National Park, Department of Hydrology and Meteorology (DHM), World Conservation Union (IUCN), Water and Energy Commission (WECS), National Agriculture Research Center (NARC) and ICIMOD, Nepal. Austrian Academic Exchange Service (ÖAD) and The World Conservation Union (IUCN, Nepal) deserve very special thanks as the institutions providing scholarship and grant to complete this research work. One man from the Institute of Hydrobiology, BOKU stood very tall in terms of cooperation to complete this work. Michael Straif (MUCH)! I am not finding words to express my gratitude to you. The Nepalese community in Vienna also deserves big thanks as it provided the homely environment whenever I was homesick. Similarly thanks also to my friends and well- wishers in Nepal. Haus Panorama 7th floor, where I was staying in Vienna was like a home with a beautiful garden comprising wonderful people from all over the world. I know there are many names missing in this text, who made valuable contributions to this work. Let me acknowledge you all. Finally, the members of my family who beared my absence many times during the studies and waiting eagerly to receive me back naturally deserve a warm heart full of thanks. And to my father I owe a debt of deepest gratitude, for the help I could not at the time appreciate: his tireless urging and prodding towards the realization of this work was crucial, and I as his son remain in his tutelage. Bibhuti ABSTRACT This work was, mainly, intended to assess the integrity of rivers in Nepal by some fish community base parameters such as the number of species, composition and the abundance. However, the variety of other information regarding fish resource and river morphology such as spatial and temporal distribution and density of fish species, size structure of a species, and substrate and physico-chemical parameters of the river are also well documented. Four different important disturbances, agriculture, urbanization, dams and weir, and industries were studied here to assess if there were any impairments on the integrity of the rivers by them. This work comprised nine rivers of Nepal in Central and Western Development Region facing those disturbances. There were three case studies for each of the four disturbances each having two sampling sites, the reference and the disturbed. Fish sampling was done by standard wading method using backpack electro-fishing gear. Four replicates of data corresponding to each major season were collected to give temporal dimension to the study. There were new findings regarding the range of distribution of many species as well as their size. The seasonal variation in the distribution of fish species was also documented for all the rivers, which were studied. In addition, the abundance and density of each species in each river were calculated to help manage the fisheries resources. The classification of rivers and river systems were also tried by using both fish community base variables and abiotic factors using cluster analysis and discriminant analysis respectively. The results for these were remarkable as both classifications corresponded to the age-old regional classification of the Nepalese river systems. Finally, it was seen that the fish population dynamics was sensitive to varieties of disturbances the rivers are facing indicating that the fish base methods of assessing water quality and river integrity could be developed for Nepalese rivers as well. It was found that the impacts of all the disturbances on river integrity were not same and thus, could not be generalized. Even the case studies of same disturbance produced mixed results pointing that the regional and seasonal factors too modify the impacts. It was found that high diversity and abundance of fish may not necessarily point toward a good water quality. The impacts of agriculture in disturbed sites were quite visible characterized by relatively higher diversity and abundance of fish indicating the nutrient input in water by runoff through cultivated areas. It was found that the impacts of agriculture also depend upon the river morphology and flow regime. The impacts of the city on the integrity of river were not found to be big enough among the cases studied. However, some trends were shown by fish community structure for this disturbance indicating that it has potential to change the river conditions. On the other hand, the impacts produced by dams and weirs were of mixed type. In general, the upstream sites supposed to be the reference site was found to be more affected than the downstream sites indicating that the upstream migration of some of the fish species was not possible due to the fragmentation of the river. Among the disturbance, the industrial disturbance was found to be the most serious one as it clearly indicated a strong relationship of the industries and the water quality and integrity of the rivers. It was even evident in Narayani River, one of the largest rivers of the country with huge water discharge. In other cases, it showed seasonal fluctuations of the impact pointing towards the biggest influential event, the monsoon, which truly rules over every aspects of the river ecology. Fish ecological studies and its numerous applications are very important to the country, as it is extremely rich in both, the fish resource and the water resource. This work is just a beginning in this direction.