Application of seaweeds to integrated multi-trophic aquaculture in southern Australia: identifying and investigating suitable native species Kathryn. H. Wiltshire Presented for the degree of Doctor of Philosophy School of Biological Sciences The University of Adelaide June 2020 Table of Contents TABLE OF CONTENTS.................................................................................................................. II THESIS ABSTRACT .................................................................................................................... VIII DECLARATION ............................................................................................................................ X ACKNOWLEDGEMENTS ............................................................................................................. XI CHAPTER 1. GENERAL INTRODUCTION ...................................................................................... 1 1 Introduction................................................................................................................. 2 1.1 Integrated multi-trophic aquaculture and the South Australian context ............... 2 1.2 Potentially suitable native seaweeds ...................................................................... 7 1.3 Selection of candidate species for research .......................................................... 11 1.4 Assessing suitability for IMTA ................................................................................ 14 1.4.1 Feasibility of propagation and cultivation ..................................................... 15 1.4.2 Suitable areas and conditions for cultivation ................................................ 19 1.4.3 Nutrient removal and storage ........................................................................ 21 2 Research aims and thesis outline .............................................................................. 21 Chapter 2. Field trials for aquaculture of native southern Australian seaweeds. ........... 23 Chapter 3. Comparing maximum entropy modelling methods to inform aquaculture site selection for novel seaweed species. ............................................................................... 25 Chapter 4. Exploring novel Rhodophyta species for aquaculture and nutrient remediation. ..................................................................................................................... 26 ii Chapter 5. Hatchery production and nutrient remediation potential of the common kelp Ecklonia radiata. ............................................................................................................... 29 Chapter 6. General discussion .......................................................................................... 31 3 References ................................................................................................................. 31 CHAPTER 2. FIELD TRIALS FOR AQUACULTURE OF NATIVE SOUTHERN AUSTRALIAN SEAWEEDS .......................................................................................................................................... 45 Abstract ................................................................................................................................ 49 1 Introduction............................................................................................................... 50 2 Materials and Methods ............................................................................................. 55 2.1. Seaweed material .................................................................................................. 55 2.2. Feasibility of reproduction .................................................................................... 56 2.3. Initial field experiment .......................................................................................... 57 2.4. Fish farm field trial ................................................................................................. 60 2.5. Chemical analyses .................................................................................................. 62 2.6. Statistics ................................................................................................................. 62 3 Results ....................................................................................................................... 64 3.1. Field trial environmental conditions ..................................................................... 64 3.2. Brown seaweed reproduction ............................................................................... 64 3.3. initial field experiment results ............................................................................... 65 3.1. Fish farm field trial results ..................................................................................... 71 iii 4 Discussion .................................................................................................................. 76 5 References ................................................................................................................. 83 CHAPTER 3. COMPARING MAXIMUM ENTROPY MODELLING METHODS TO INFORM AQUACULTURE SITE SELECTION FOR NOVEL SEAWEED SPECIES ............................................ 91 Supplementary material ..................................................................................................... 107 Supplementary tables ................................................................................................. 107 Supplementary figures ................................................................................................ 112 CHAPTER 4. EXPLORING NOVEL RHODOPHYTA SPECIES FOR AQUACULTURE AND NUTRIENT REMEDIATION ........................................................................................................................ 122 Abstract .............................................................................................................................. 126 1 Introduction............................................................................................................. 127 2 Materials and Methods ........................................................................................... 130 2.1 Seaweed material ................................................................................................ 130 2.2 Initial species comparison experiment ................................................................ 130 2.3 Temperature response experiment .................................................................... 132 2.4 Further investigation of S. robusta ...................................................................... 134 2.4.1 Light and ammonium responses .................................................................. 134 2.4.2 Nitrogen uptake rates .................................................................................. 137 2.4.3 Explant production ....................................................................................... 139 2.5 Chemical analyses ................................................................................................ 140 2.6 Bayesian methods ............................................................................................... 141 iv 3 Results ..................................................................................................................... 142 3.1 Initial species comparison results ........................................................................ 142 3.2 Temperature responses of S. robusta and G. australe ........................................ 143 3.3 Further investigations of Solieria robusta ........................................................... 144 3.3.1 Light and ammonium responses .................................................................. 144 3.3.2 Nitrogen uptake rates .................................................................................. 150 3.3.3 Explant production ....................................................................................... 151 4 Discussion ................................................................................................................ 153 4.1 Suitability for IMTA of the four species investigated .......................................... 153 4.2 Temperature, light and nutrient responses ........................................................ 155 4.3 Informing suitable sites and cultivation periods ................................................. 158 4.4 Seedstock production .......................................................................................... 160 4.5 Conclusions .......................................................................................................... 162 5 References ............................................................................................................... 163 Supplementary material ..................................................................................................... 171 Supplementary results for tissue N data analysis (section 3.1). .................................... 171 Supplementary results for Solieria robusta explant production data analysis (section 3.3.3) ............................................................................................................................... 173 CHAPTER 5. HATCHERY PRODUCTION AND NUTRIENT REMEDIATION POTENTIAL OF THE KELP ECKLONIA RADIATA ...............................................................................................................