Chapter 1 Introduction
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EFFECTS OF ENVIRONMENTAL FACTORS, PHYSICAL BARRIERS AND SEASON ON THE FISH COMMUNITY COMPOSITION OF THE LOWER OTTAWA AND MISSISSIPPI RIVER SYSTEMS AS DETERMINED FROM QUANTITATIVE ELECTROFISHING by Andrew G. Lowles A thesis submitted to the Department of Biology In conformity with the requirements for the degree of Master of Science Queen’s University Kingston, Ontario, Canada (January 2013) © Andrew G. Lowles ABSTRACT Environmental and physical conditions are considered primary drivers of fish community assemblages. The anthropogenic alteration of aquatic ecosystems is implicated as a primary threat to fisheries worldwide. In riverine ecosystems, river-wide barriers may alter natural fluvial processes and hinder fish movement through the system. In this study, I use data collected from two successive years (2008 and 2009) of intensive quantitative electrofishing Casselman and Marcogliese (2008, 2009) performed in different seasons (late fall and late summer) on the lower Ottawa and Mississippi River systems, Ontario, to investigate the effects of sampling season, distance from the river mouth, water temperature, conductivity, rank of velocity and dams on fish abundance, species richness and the Shannon-Weiner Index (SWI) as a measure of species diversity. Sampling in late summer, compared with late fall, resulted in greater species richness and diversity. Colder water temperature affected community composition, and species richness decreased upstream, while diversity did not change. In both seasons, the distance from the river mouth influenced fish community composition, whereas dams appeared to have no effect. This suggests that the continuous gradient model of the River Continuum Concept (RCC) would be applicable in these fragmented systems, which are not heavily altered by fractionation. To effectively manage cost and accuracy when collecting fish community data in large rivers, it is essential to sample strategically during seasons likely to maximize diversity and richness. Sampling intensively during warm water months in various river reaches would likely provide the most complete representation of fish assemblage. ii CO-AUTHORSHIP This thesis conforms to the traditional format as outlined by the School of Graduate Studies and Research. Lowles, A.G., J.M. Casselman, and W.A Nelson. 2013. Effects of environmental factors, physical barriers and season on the fish community composition of the lower Ottawa and Mississippi Rivers systems as determined from quantitative electrofishing. iii ACKNOWLEDGEMENTS I would like to begin by thanking my supervisors Dr. John Casselman and Dr. William Nelson for having me as their student, and for their continued support and guidance throughout my thesis. Your guidance and mentorship has been instrumental in my development over the past three years. I would like to thank you both for providing me the opportunity to pursue my interest in fisheries science and advance my abilities as a researcher. I appreciate the additional support and guidance of my supervisory committee member, Dr. Shelley Arnott, and examiner, Dr. Paul Martin. I would like to thank Dr. Robert Montgomerie for all his help throughout my time at Queen’s University. I would like to thank Dr. John Casselman and Lucian A. Marcogliese for allowing me to use the quantitative electrofishing data collected by AFishESci Inc. Without this data my thesis would not have been possible. The analytical support and advice by Nathan McClure and Andy Wong have been a great asset throughout my project. Without their knowledge of R programming, data analysis would have been extremely tedious. I would like to thank my family and friends for their support and encouragement throughout my studies. I would like to thank Dan and Lyla Galley for their continuing support throughout my time in Kingston. My parents, Doug and Marilyn, my brother Steve, and sister-in-law, Holley, have been a tremendous support and inspiration through all aspects of my life. Finally, I want to thank my wife, Erin, and daughter Kendall for their love and encouragement throughout my studies. Without their support, none of this would have been possible. You are my motivation and the foundation on which the rest of my life is built. iv TABLE OF CONTENTS Abstract................................................................................................................................ii Co-Authorship....................................................................................................................iii Acknowledgements.............................................................................................................iv Table of Contents.................................................................................................................v List of Abbreviations........................................................................................................viii List of Tables......................................................................................................................ix List of Figures.....................................................................................................................xi Chapter 1 Introduction ........................................................................................................1 Chapter 2 Review of Literature............................................................................................6 2.1 Fish Community Composition and Structure and Fisheries Management.................7 2.2 Niche Concept and Competition................................................................................8 2.3 Environmental Conditions........................................................................................10 2.4 River Continuum Concept........................................................................................12 2.5 Impact of River Barriers on Fish...............................................................................14 2.6 Fish Sampling Techniques........................................................................................15 2.7 Species and Fish Community Diversity...................................................................17 2.8 Research Rationale and Study Objectives................................................................19 Chapter 3 Materials and Methods.....................................................................................20 3.1 Rivers Studied...........................................................................................................20 3.2 Sampling Location Criteria.......................................................................................21 3.3 Data Collection.........................................................................................................22 3.4 Richness and Diversity.............................................................................................25 v 3.5 Annual Changes in Fish Assemblages......................................................................26 3.6 Environmental Variables and Fish Assemblages......................................................27 3.7 Below-Dam and Above-Dam Comparisons.............................................................28 Chapter 4 Results...............................................................................................................40 4.1 Fish Abundance, Occurrence, Composition and Density.........................................40 4.2 Species Richness.......................................................................................................42 4.3 Species Diversity......................................................................................................43 4.4 Effects of Physical and Environmental Variables....................................................43 4.4.1 Distance to River Mouth.....................................................................................43 4.4.2 Water Temperature.............................................................................................44 4.4.3 Conductivity........................................................................................................45 4.4.4 Velocity...............................................................................................................45 4.5 Annual Change in Species Composition...................................................................46 4.6 Fish Assemblages and Physical and Environmental Variables................................47 4.7 Below-Dam and Above-Dam Comparisons.............................................................47 Chapter 5 Discussion.........................................................................................................79 5.1 Fish Abundance and Density....................................................................................79 5.2 Species Richness and Diversity................................................................................80 5.3 Changes in Species Composition Between Years.....................................................81 5.4 Effect of Dams on Water Velocity............................................................................82 5.5 Effect of Physical Distance and Reach Length on Richness and Diversity..............83 5.6 Anthropogenic Factors Affecting Richness and Diversity.......................................85 5.7 Effect of Environmental Variables...........................................................................86 vi Chapter 6 Conclusions and