Coastal floodplain management in eastern Australia: barriers to fish and invertebrate recruitment in acid sulphate soil catchments F.J. Kroon, A.M. Bruce, G.P. Housefield & R.G. Creese NSW Department of Primary Industries Port Stephens Fisheries Centre Private Bag 1, Nelson Bay, NSW 2315 Australia FRDC Project No. 98/215 August 2004 NSW Department of Primary Industries - Fisheries Final Report Series No. 67 ISSN 1449-9967 Coastal floodplain management in eastern Australia: barriers to fish and invertebrate recruitment in acid sulphate soil catchments August 2004 Authors: F.J. Kroon, A.M. Bruce, G.P. Housefield & R.G. Creese Published By: NSW Department of Primary Industries (now incorporating NSW Fisheries) Postal Address: Private Bag 1, Nelson Bay, NSW 2315 Internet: www.fisheries.nsw.gov.au NSW Department of Primary Industries and the Fisheries Research & Development Corporation This work is copyright. 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ISSN 1449-9967 (Note: Prior to July 2004, this report series was published as the ‘NSW Fisheries Final Report Series’ with ISSN number 1440-3544) Contents i TABLE OF CONTENTS TABLE OF CONTENTS................................................................................................................................. I LIST OF TABLES.........................................................................................................................................III LIST OF FIGURES.........................................................................................................................................V ACKNOWLEDGEMENTS.........................................................................................................................VII NON TECHNICAL SUMMARY.............................................................................................................. VIII 1. GENERAL INTRODUCTION.......................................................................................... 11 1.1. Background.....................................................................................................................11 1.2. Need................................................................................................................................12 1.3. Objectives and the achievement of those objectives.......................................................13 2. METHODS TO ASSESS IMPACT OF FLOODGATES AND FLOODGATE MANAGEMENT ON FISH PASSAGE AND WATER AND HABITAT QUALITY IN COASTAL FLOODPLAINS, NSW ........................................................................................ 16 2.1. Introduction ....................................................................................................................16 2.2. Sampling sites in the Clarence River..............................................................................16 2.2.1. Sampling methods ........................................................................................... 21 2.2.2. Data analyses .................................................................................................. 24 3. IMPACT OF FLOODGATES ON FISH PASSAGE AND WATER AND HABITAT QUALITY IN THE CLARENCE RIVER FLOODPLAIN, NSW.................................................... 32 3.1. Introduction ....................................................................................................................32 3.2. Methods ..........................................................................................................................33 3.2.1. Sampling sites.................................................................................................. 33 3.2.2. Sampling methods ........................................................................................... 33 3.2.3. Data analyses .................................................................................................. 33 3.3. Results ............................................................................................................................34 3.3.1. General............................................................................................................ 34 3.3.2. Species assemblages (abundance data)........................................................... 35 3.3.3. Species assemblages (biomass data)............................................................... 39 3.3.4. Water quality and ANZECC guidelines........................................................... 42 3.4. Discussion.......................................................................................................................44 3.4.1. Life history characteristics.............................................................................. 45 4. THE EFFECTIVENESS OF FLOODGATE MANAGEMENT IN IMPROVING FISH PASSAGE AND WATER AND HABITAT QUALITY IN THE CLARENCE RIVER, NSW ......... 47 4.1. Introduction ....................................................................................................................47 4.2. Methods ..........................................................................................................................47 4.2.1. Opening regimes of gated drainage systems ................................................... 47 4.2.2. Sampling methods ........................................................................................... 47 4.2.3. Data analyses .................................................................................................. 52 4.3. Results ............................................................................................................................53 4.3.1. General............................................................................................................ 53 4.3.2. Opening regimes of gated drainage systems ................................................... 55 4.3.3. Species abundance .......................................................................................... 57 4.3.4. Species biomass............................................................................................... 64 4.3.5. Relationship between floodgate opening and species richness and diversity.. 74 4.3.6. Effect of two different gate structures on fish passage.................................... 74 4.3.7. Water quality and ANZECC guidelines........................................................... 80 4.4. Discussion.......................................................................................................................83 Coastal floodplain management (Kroon, Bruce, Housefield, Creese) FRDC Project No. 98/215 ii Contents 5. TEMPORAL PATTERNS OF RECRUITMENT TO THE CLARENCE RIVER FLOODPLAIN BY COMMERCIALLY SIGNIFICANT FISH AND PRAWN SPECIES .......................................................................................... 85 5.1. Introduction....................................................................................................................85 5.2. Methods.......................................................................................................................... 85 5.3. Results and Discussion................................................................................................... 86 5.3.1. Sandy Sprat......................................................................................................86 5.3.2. Silver Biddy......................................................................................................86 5.3.3. Yellowfin Bream...............................................................................................87 5.3.4. Tarwhine ..........................................................................................................87 5.3.5. Flat-tail Mullet.................................................................................................88 5.3.6. Sea Mullet ........................................................................................................88 5.3.7. School Prawn...................................................................................................88 5.3.8. Eastern King Prawn.........................................................................................89 5.4. Summary of critical recruitment periods........................................................................ 90 6. A FLUVIARIUM WITH CONTROLLED WATER QUALITY FOR PREFERENCE - AVOIDANCE EXPERIMENTS WITH FISH AND INVERTEBRATES ................... 101 6.1. Introduction.................................................................................................................. 101 6.2. Methods........................................................................................................................ 102 6.2.1. Design considerations of fluviarium ..............................................................102 6.2.2. Precise