NEARSHORE FISH COMMUNITY STRUCTURE IN THE SOUTHWEST BAY OF FUNDY AND NORTHWEST ATLANTIC: COMPARING ASSEMBLAGES ACROSS MULTIPLE SPATIAL AND TEMPORAL SCALES by Collin Arens B.Sc. (Hon), University of New Brunswick, 2003 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Master’s of Science In the Graduate Academic Unit of Biology Supervisors: David Methven, Ph.D., Dept of Biology, CRI, UNB Saint John Kelly Munkittrick, Ph.D., Dept of Biology, CRI, UNB Saint John Examining Board: Matthew Litvak, Ph.D., Dept. of Biology, UNB Saint John Keith Dewar, Ph.D., Faculty of Business, UNB Saint John This thesis has been accepted by the Dean of Graduate Studies THE UNIVERSITY OF NEW BRUNSWICK April, 2007 © Collin Arens, 2007 ABSTRACT The purpose of this investigation was to assess seasonal, tidal/diel and regional variation in the nearshore fish assemblage of the southwest Bay of Fundy, as well as identify overlying patterns in taxonomic and functional guild structure throughout coastal shallows of the northwest Atlantic. Within the southwest Bay of Fundy species richness and abundance varied seasonally and were correlated with water temperature exhibiting distinct cold and warm water assemblages throughout the year. Over a 24 hour period greater species richness and abundance were observed among samples collected at low tide, with larger fishes captured at night. Regionally, assemblage structure was largely influenced by habitat type with geographic proximity among sites having little direct influence on the structure observed. Throughout the northwest Atlantic taxonomic structure reflected existing biogeographic provinces with the Labrador, Acadian and Virginian provinces represented, while functional guild structure exhibited latitudinal gradients with respect to ecological type and egg dispersal. i ACKNOWLEDGEMENTS There are many people who helped me in many different ways throughout the course of this project and I owe each of them a debt of gratitude. In particular I would like to thank my mother, Kathy Read for her support and encouragement over the years. I would like to thank my supervisors, Dr. Dave Methven and Dr. Kelly Munkittrick for their unending patience, guidance and feedback throughout this study, as well as my supervisory committee Dr. Simon Courtenay and Dr. Allen Curry for their suggestions and comments. I would also like to thank Kevin Shaughnessey, Mark Pokorski, Jason Casselman, Frederic Vandeperre and Joesph Pratt for their assistance throughout the field sampling; especially during the early mornings and cold winter months when I’m sure there were other places they would have preferred to be. Finally, thank you to my friends and fellow graduate students; Chris Blanar, Sandy Brasfield, Jason Casselman, Karen Gormley, Lindsay Jennings, Roshini Kassie, Mark Pokorski, Kevin Shaughnessey, and my partner Leslie Carroll, who were always willing to lend an ear or put on a pair of waders when I was in need. Without the assistance of all of these people this project would not have been possible. ii TABLE OF CONTENTS ABSTRACT ....................................................................................................................... i ACKNOWLEDGEMENTS .............................................................................................. ii TABLE OF CONTENTS ................................................................................................. iii LIST OF TABLES ............................................................................................................ v LIST OF FIGURES ....................................................................................................... viii LIST OF SYMBOLS AND ABBREVIATIONS ............................................................ xi CHAPTER 1: GENERAL INTRODUCTION ............................................................... 12 1.1 Introduction .................................................................................................. 13 1.2 Literature Cited ............................................................................................ 16 CHAPTER 2: SPATIAL AND TEMPORAL VARIATION IN THE NEARSHORE FISH ASSEMBLAGE OF THE SOUTHWEST BAY OF FUNDY .............................. 19 2.1 Abstract ........................................................................................................ 20 2.2 Introduction .................................................................................................. 21 2.3 Materials and Methods ................................................................................. 24 2.3.1 Study Area .......................................................................................... 24 2.3.2 Seasonal Sampling (Study 1) .............................................................. 24 2.3.3 Additional Sampling (Studies 2 & 3) ................................................. 26 2.3.4 Data Analyses ..................................................................................... 27 2.3.5 Functional Guild Classification .......................................................... 29 2.4 Results .......................................................................................................... 37 2.4.1 Seasonal Variation .............................................................................. 37 2.4.2 Functional Guilds ................................................................................ 41 2.4.3 Regional Variation .............................................................................. 42 2.4.4 Tidal and Diel Variation ..................................................................... 44 2.5 Discussion .................................................................................................... 46 2.5.1 Seasonal Variation .............................................................................. 46 2.5.2 Functional Guilds ................................................................................ 49 2.5.3 Regional Variation .............................................................................. 52 2.5.4 Tidal and Diel Variation ..................................................................... 53 2.6 Conclusion .................................................................................................... 56 2.7 Acknowledgements ...................................................................................... 57 2.8 Literature Cited ............................................................................................ 85 iii CHAPTER 3: LATITUDINAL VARIATION IN TAXANOMIC AND FUNCTIONAL GUILD STRUCTURE OF NEARHSORE FISH ASSEMBLAGES OF THE NORTHWEST ATLANTIC ........................................................................................... 91 3.1 Abstract ........................................................................................................ 92 3.2 Introduction .................................................................................................. 93 3.3 Materials and Methods ................................................................................. 95 3.3.1 Sources of Data ................................................................................... 95 3.3.2 Data Analyses ..................................................................................... 96 3.3.3 Functional Guild Classification .......................................................... 97 3.4 Results ........................................................................................................ 100 3.4.1 Taxonomic Analyses ........................................................................ 101 3.4.2 Functional Guild Analyses ............................................................... 101 3.5 Discussion .................................................................................................. 104 3.6 Acknowledgements .................................................................................... 110 3.7 Literature Cited .......................................................................................... 133 CHAPTER 4: GENERAL SUMMARY AND CONCLUSIONS ................................ 136 4.1 Summary .................................................................................................... 137 4.1.1 Southwest Bay of Fundy Nearshore Fish Assemblage ..................... 137 4.1.2 Northwest Atlantic ............................................................................ 139 4.2 Conclusions ................................................................................................ 140 4.2.1 Functional Guilds .............................................................................. 140 4.2.2 Implications for Management of Nearshore Areas ........................... 142 4.2.3 Future Research ................................................................................ 142 4.3 Literature Cited .......................................................................................... 144 VITA iv LIST OF TABLES Table 2.1: Name, number, location and dominant substrate type at the 16 sites sampled in this study. Study indicates sites sampled during seasonal (1), regional (2) and tidal/diel (3) studies. See Methods for details. ..................................... 58 Table 2.2: Functional guild classification used in this study during the 13 months of sampling at sites 1-3 and 12-14. Abbreviations as follows: Ecological Type - Marine Migrant (MM), Marine Straggler (MS), Estuarine Resident (ER), Estuarine