CAIRNS SHIPPING DEVELOPMENT PROJECT Revised Draft Environmental Impact Statement Chapter B7: Marine Ecology TABLE OF CONTENTS CHAPTER B7: MARINE ECOLOGY _______________________________________________ I B7.1 Introduction......................................................................................................................................................... 1 B7.1.1 Nomenclature and Terminology .................................................................................................................................... 1 B7.2 Existing Situation ............................................................................................................................................... 3 B7.2.1 Methodology .................................................................................................................................................................... 3 B7.2.2 Background ...................................................................................................................................................................... 4 B7.2.3 Marine Protected Areas and Wetlands of Conservation Significance ..................................................................... 5 B7.2.4 Mangroves and Saltmarsh ............................................................................................................................................. 7 B7.2.5 Hard Benthic Substrata and Associated Communities ............................................................................................ 24 B7.2.6 Soft Sediment Habitat and Associated Communities .............................................................................................. 40 B7.2.7 Marine Species of Conservation Significance .......................................................................................................... 55 B7.2.8 Exotic Marine Species and Pests ............................................................................................................................... 63 B7.2.9 Fish and Shellfish Resources ...................................................................................................................................... 64 B7.3 Assessment of Potential Impacts .................................................................................................................. 81 B7.3.1 Overview ........................................................................................................................................................................ 81 B7.3.2 Methodology .................................................................................................................................................................. 85 B7.3.3 Direct Modification of Benthic Habitats and Communities from Dredging, Dredged Material Placement, Wharf Upgrades and Pipeline Trenching ............................................................................................................................................. 89 B7.3.4 Increased Suspended Sediment Concentrations and Sedimentation from Dredging ......................................... 93 B7.3.5 Tailwater Release from Northern Sands DMPA ..................................................................................................... 109 B7.3.6 Interactions between Marine Fauna and Vessels .................................................................................................. 115 B7.3.7 Acoustic Effects to Marine Fauna from Wharf Upgrade Works ............................................................................ 118 B7.3.8 Other Indirect Interactions between Vessels and Marine Receptors .................................................................. 118 B7.3.9 Exposure of Marine Flora and Fauna to Debris, Spills and Dredging-Borne Contaminants ............................ 119 B7.4 Recommended Mitigation Measures .......................................................................................................... 121 B7.4.1 Direct Impacts to Soft Sediment Areas .................................................................................................................... 121 B7.4.2 Impacts to Commercial Fisheries Species .............................................................................................................. 121 B7.4.3 Dredge Plume and Sedimentation Impacts ............................................................................................................ 121 B7.4.4 Impacts of Tailwater Releases on Flora and Fauna .............................................................................................. 122 B7.4.5 Impacts to Megafauna ................................................................................................................................................ 122 B7.4.6 Other Marine Vessel Impacts .................................................................................................................................... 123 B7.4.7 Residual Impacts and Assessment Summary ........................................................................................................ 124 B7.5 References ..................................................................................................................................................... 132 List of Figures Figure B7-1 Location of the Study Area and Project Areas. ................................................................................................... 2 Figure B7-2 Location of Conservation Areas of relevance to the marine ecology aspects of the project. ...................... 6 Figure B7-3 Remnant mangrove and saltmarsh communities based on Regional Ecosystem mapping. ....................... 9 Figure B7-4 Present (2015) Seagrass distribution in Cairns Harbour and Trinity Inlet. ................................................... 14 Figure B7-5 Present (2015) Seagrass distribution in Cairns Harbour and Trinity Inlet. ................................................... 15 Figure B7-6 Seagrass biomass (above) and cover (below) for the Cairns region between 2001 and 2015 (Error Bars – Standard Error). .......................................................................................................................................................... 16 Figure B7-7 Changes in seagrass meadow extent between 2005 and 2015 for the Cairns Esplanade and Ellie point. .......................................................................................................................................................................................... 18 Figure B7-8 Changes in seagrass meadow extent between 2005 and 2015 for meadows south-west of False Cape. .......................................................................................................................................................................................... 19 Figure B7-9 Changes in seagrass meadow extent between 2005 and 2015 for meadows in southern Trinity Inlet. .. 20 Figure B7-10 Comparison of seagrass meadow area in the western and eastern sides of Cairns Harbour; 1984, 1988, 1993, 2001 and 2012. ........................................................................................................................................ 21 Figure B7-11 Seagrass Monitoring Meadow Condition in Cairns Harbour, October 2013. ............................................. 23 Figure B7-12 East Trinity (A-F) and False Cape (G-J) Shoreline Assessment: Stilt Mangroves (Rhizophora stylosa) and Dense Oysters in the Upper Intertidal Zone (A); Encrusting Tubeworms cover the Lower Intertidal Zone(B); Filter Feeding Holothurians (Pseudocolchirus violaceus) were Common (C); Dendronephthyid Soft Coral (D); Brown Macro Algae (E); the Baler Shell (Melo amphora) (F) ; Dense Boulder Field (G); Turfing Algae and Halimeda (H); Hard Coral (Favia stelligera) (I) and Sargassum (J). ................................................... 25 Figure B7-13 GBRMP Gazetteer Reefs in the surrounding area. ....................................................................................... 26 Figure B7-14 Reef Communities at Rocky Island: Looking South across the Reef Flat (A); Halimeda, the Hard Coral Galaxea (B) and Soft Coral (Briareum) (C) were Dominant along the Reef Edge; Microatoll with Turbinaria and Sinularia (D); Hard Coral (Goniopora) (E); Dendrophyllid Hard Coral (F); Epaulette Shark (Hemiscyllium ocellatum) (G); Green Turtle (Chelonia mydas) (H); Ornate Crayfish (Panulirus ornatus) (I); and Bare Staghorn Coral (Acropora) Remnant Substrate (J). ................................................................................................. 27 Figure B7-15 Percentage Cover of (i) Broad Benthic Groups (top) and (ii) Numerically Dominant Taxa (bottom). Note: Odd Number Transects at Double Island were Located on the Upper Edge of the Reef Slope, even Number Transects were Located on the Deep Margin of the Reef Slope. ............................................................ 32 Figure B7-16 Non-metric MDS Ordination – Reef Communities. ........................................................................................ 33 Figure B7-17 Coral, algae and seagrass communities at Double Island Reef. ................................................................. 35 Figure B7-18 Coral, algae and seagrass communities at Rocky Island Reef. .................................................................. 36 Figure B7-19 Reef Communities at Double Island Reef: Sparse Seagrass over Sand (A); Dense