Structure and Dynamics of Rockpool Fish Assemblages in Southeastern Australia Shane P
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University of Wollongong Research Online University of Wollongong Thesis Collection University of Wollongong Thesis Collections 2002 Structure and dynamics of rockpool fish assemblages in Southeastern Australia Shane P. Griffiths University of Wollongong Recommended Citation Griffiths, Shane P., Structure and dynamics of rockpool fish assemblages in Southeastern Australia, Doctor of Philosophy thesis, Department of Environmental Science, University of Wollongong, 2002. http://ro.uow.edu.au/theses/1381 Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library: [email protected] For my parents, Alan and Denise. For never losing faith. STRUCTURE AND DYNAMICS OF ROCKPOOL FISH ASSEMBLAGES IN SOUTHEASTERN AUSTRALIA. A thesis submitted in fulfilment of the requirements for the award of the degree DOCTOR OF PHILOSOPHY from UNIVERSITY OF WOLLONGONG by SHANE P. GRIFFITHS ENVIRONMENTAL SCIENCE 2002 ii "The intertidal zone is the place of origin of most fish groups. From there they spread seaward onto the shelf platform and into the open sea and landward to deltaic (and into the rivers) andsupratidal areas" (Shultze, 1999). Frontispiece. A typical intertidal landscape during low tide at Maloney's Bay, Bass Point, New South Wales, Australia. iii DECLARATION I, Shane P. Griffiths, declare that this thesis, submitted in fulfilment ofthe requirements for the award of Doctor of Philosophy, in Environmental Science, University of Wollongong, is wholly my own work unless otherwise referenced or acknowledged. The document has not been submitted for qualifications at any other academic institution. Shane Paul Griffiths 24 October 2002 IV Table of Contents Title Page i Frontispiece ii Declaration iii Table of Contents iv Acknowledgments ix Papers and manuscripts associated with thesis chapters xii Manuscripts associated with this thesis xiii Abstract xiv List of Tables xviii List of Figures xxvii List of Plates xxxv Chapter 1: General introduction 1 Definitions of commonly used terms 9 Description of the study region 11 Chapter 2: Methods for sampling rockpool fishes 16 Introduction 16 Materials and Methods 20 Experiment 1: Determination of a desirable clove oil concentration 20 Experiment 2: Effectiveness of clove oil as a quantitative sampling 21 method Census of fishes 22 Statistical analyses 23 Results 25 Experiment 1: Determination of a desirable clove oil concentration 25 Experiment 2: Effectiveness of clove oil as a quantitative sampling 28 method Discussion 33 Desirable concentration of clove oil 33 Comparisons of sampling methods 3 5 Chapter 3: Overview of rockpool fish assemblages 39 Introduction 39 Materials and Methods 43 Study sites 43 Categorisation of fishes 43 Results 47 Taxonomic composition 47 Residential categories 53 Biogeographic affinities 54 Discussion 56 Comparisons with other rockpool fish communities 56 Comparisons with other Australian rockpool fish communities 60 Residency and biogeographic affinities of NSW rockpool fishes 63 Chapter 4: Spatial and temporal variation in rockpool fish assemblages 66 Introduction 66 Materials and Methods 69 Study 1: Long-term spatial and temporal variation in fish assemblages 69 Study 2: Large-scale spatial variation in fish assemblages 70 Data collection: Study 1 and 2 70 Statistical analyses 72 Univariate analyses 72 Multivariate analyses 73 Results 75 Study 1: Long-term spatial and temporal variation in fish assemblages 75 Variation in the physico-chemical environment 75 Numbers of species and individuals 75 Relationships with environmental variables 82 Variation in abundance of common species 86 Fish assemblage structure 90 Among-location comparisons 90 Within-location comparisons 93 Length-frequency distributions of common species 97 Study 2: Large-scale spatial variation in fish assemblages 102 Discussion 110 Chapter 5: Effects of rockpool elevation on fish assemblage structure 116 Introduction 116 Materials and Methods 118 Study sites and collection of fishes 118 Statistical analyses 120 Results 121 Physico-chemical environment 121 Numbers of species and individuals 121 Fish assemblage structure 126 Length-frequency distributions 130 Discussion 132 Chapter 6: Recolonisation of rockpools by fishes 138 Introduction 138 Materials and Methods 141 Experimental design 141 Statistical analyses 144 Competition 146 Results 147 Numbers of species and individuals 147 Variation in abundance of major recolonising species 153 Fish assemblage structure 158 Length-frequency distributions and competition 160 Discussion 165 Vll Chapter 7: Movements and homing of rockpool fishes 172 Introduction 172 Materials and Methods 175 Experiment 1: Assessment of tag utility 175 Experiment 2: Pilot study of fish homing 159 Experiment 3: Main homing study 180 Study sites and fish collection 180 Statistical analyses 183 Results 183 Experiment 1: Assessment of tag utility 183 Experiment 2: Pilot study of fish homing 185 Experiment 3: Main homing study 186 Discussion 191 Utility of visible implant tags for marking small rockpool fishes 191 Homing experiments 193 Displacement distance and homing success 195 Effects of fish size on homing success 196 Time at liberty and homing success 198 Other factors influencing homing success 199 Chapter 8: Effects of habitat complexity on rockpool fish assemblages 201 Introduction 201 Materials and Methods 205 Study design 205 Statistical analyses 209 Results 210 Numbers of species and individuals 210 Variation in abundance of individual species 215 Fish assemblage structure 219 Manipulation 1 219 Manipulation 2 222 Length-frequency distributions 225 Discussion 228 Suspended cover (ASUs) 228 Substratum heterogeneity 231 Chapter 9: General discussion 235 Structure and spatial variation in fish assemblages 236 The role of fish movements in rockpool fish assemblages 239 The role of cover in rockpool fish assemblages 244 Modelling the dynamics of rockpool fish assemblages 246 Limitations ofthe model and directions for future research 249 Implications for conservation and management 252 Conclusions 254 References 256 Appendix 291 Appendix 1. Published scientific paper from work reported in Chapter 2 of 291 this thesis. Appendix 2. Published scientific paper from work reported in Chapter 7 of 303 this thesis. Appendix 3. Photographs and descriptions ofthe locations sampled during 306 studies in this thesis. Photographs after Smith (2001), except for Puckey's Bombora, Marsden Head, Mollymook Point, Tuross Heads and Wagonga Head, which were taken by the author. Appendix 4. Instructions for the use of Visible Implant Alphanumeric tags 311 by Northwest Marine Technologies. Appendix 5. Instructions for the use of Visible Implant Fluorescent 313 Elastomer tags by Northwest Marine Technologies. IX ACKNOWLEDGMENTS To say that a PhD thesis can be one ofthe greatest pieces of work anyone could imagine compiling, in my opinion, would be a drastic understatement. Many times I considered the task all too difficult but only now after finally coming to the end and compiling all my research findings in a single volume do I realise how fortunate I have been to have the opportunity to pursue my personal research in ichthyology. I have always been a keen recreational fisher, and in the early 1980's when I saw Dr Julian Pepperell talk on the television program "Go Fish Australia" about the fascinating migrations of tagged game fish, I knew fisheries was the only field I wanted to work in. From my first day of high school work experience at NSW Fisheries at Cronulla back in August 1991,1 was determined to become an ichthyologist, perhaps 11 years later but nonetheless I reached my goal. This exhausting, but very rewarding, journey would not have been possible without my two supervisors, Associate Professors Ron West and Andy Davis of the University of Wollongong. I extend my most sincere thanks to them for providing me with encouragement, helpful suggestions using their extensive knowledge of marine ecology, and for enduring the arduous task of critically reviewing drafts of this thesis. Without these two people production of this thesis would never have been possible. I owe Jade Bulter an enormous amount of thanks, not only for helping me with many aspects of my work in her own free time, but for tolerating my obsession with fish for the past five years. I also owe thanks to a large number of people who helped out in many ways and for each task I will list them alphabetically. x I thank David Barker, Bruce Pease and Veronica Silberschneider from NSW Fisheries, Robin Gibson, Mike Chotkowski and Donald Buth who critically reviewed drafts of Chapter 1 in the form of a scientific paper published in the Journal of Fish Biology. Kirsten Benkendorff generously allowed use of her aquaria for laboratory experiments. Jade Butler, Adrian Ferguson, Alisa Eustace, Alan Griffiths, and Kane Organ assisted with fieldwork and laboratory experiments. I am grateful to Ken Russell, Mick Gregory, Catherine Pfister and Marti Anderson for statistical advice. Rob Whelan, Kris French and Bill Buttemer are thanked for helpful discussions. Glenn Johnstone generously donated nets and preliminary tagging equipment. Jerermy Nicol and Eric Hockey for supplying equipment needed for the manipulation experiments. Staff at the Environmental Science unit are thanked, namely Professor John Morrison for accepting me into his department and Sandra Quinn for help with all aspects of administration. Peter Bergman and Daniel Thompson from Northwest