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Eradicating and Preventing the Spread of the Invasive Alga Caulerpa Taxifolia in NSW

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Eradicating and Preventing the Spread of the Invasive Alga Caulerpa Taxifolia in NSW Eradicating and preventing the spread of the invasive alga Caulerpa taxifolia in NSW R.G.Creese1, A.R. Davis2 and T.M.Glasby1 1. NSW Fisheries, Port Stephens Fisheries Centre, Private Bag 1, Nelson Bay, NSW 2315, Australia. 2. School of Biological Sciences, University of Wollongong, NSW 2522, Australia. Project No. 35593 June 2004 NSW Fisheries Final Report Series No. 64 ISSN 1440-3544 Eradicating and preventing the spread of the invasive alga Caulerpa taxifolia in NSW R.G.Creese1, A.R. Davis2 and T.M.Glasby1 1. NSW Fisheries, Port Stephens Fisheries Centre, Private Bag 1, Nelson Bay, NSW 2315, Australia. 2. School of Biological Sciences, University of Wollongong, NSW 2522, Australia. Project No. 35593 June 2004 NSW Fisheries Final Report Series No. 64 ISSN 1440-3544 Research and the collation of information presented in this report was undertaken with funding provided by the Australian Government’s Natural Heritage Trust. The views and opinions expressed in this report are those of the authors and do not reflect those of the Australian Government or the Minister for the Environment and Heritage. The report may be cited as: Creese R.G., Davis A.R. and Glasby T.M. (2004) Eradicating and Preventing the Spread of Caulerpa taxifolia in NSW Copies of the report may be borrowed from: The Library Department of Environment & Heritage GPO Box 787 Canberra ACT 2601 AUSTRALIA Or The Library NSW Fisheries PO Box 21 Cronulla NSW 2230 AUSTRALIA NSW Fisheries This work is copyright. Except as permitted under the Copyright Act (Cth), no part of this reproduction may be reproduced by any process, electronic or otherwise, without the specific written permission of the copyright owners. Neither may information be stored electronically in any form whatsoever without such permission. DISCLAIMER The publishers do not warrant that the information in this report is free from errors or omissions. The publishers do not accept any form of liability, be it contractual, tortuous or otherwise, for the contents of this report for any consequences arising from its use or any reliance placed on it. The information, opinions and advice contained in this report may not relate to, or be relevant to, a reader’s particular circumstance. ISSN 1440-3544 Contents i TABLE OF CONTENTS TABLE OF CONTENTS................................................................................................................................. I LIST OF TABLES.........................................................................................................................................III LIST OF TABLES.........................................................................................................................................III LIST OF FIGURES....................................................................................................................................... IV LIST OF FIGURES....................................................................................................................................... IV LIST OF PLATES......................................................................................................................................... VI ACKNOWLEDGEMENTS.........................................................................................................................VII EXECUTIVE SUMMARY........................................................................................................................ VIII 1. INTRODUCTION & BACKGROUND ..........................................................................................1 1.1. Invasive Caulerpa taxifolia..........................................................................................................1 1.2. Caulerpa taxifolia infestations in NSW.......................................................................................2 1.3. This report....................................................................................................................................4 2. MAPPING THE SPREAD OF CAULERPA TAXIFOLIA IN NSW....................................................6 2.1. Field survey methods for Caulerpa taxifolia ...............................................................................6 2.1.1. Areas already affected by C. taxifolia .......................................................................... 8 2.1.2. Areas likely to be affected by C. taxifolia ..................................................................... 8 2.1.3. Areas considered unlikely to be affected by C. taxifolia............................................... 8 2.2. Creating final maps......................................................................................................................8 2.3. Sites with C. taxifolia...................................................................................................................8 2.3.1. Lake Macquarie............................................................................................................ 9 2.3.2. Pittwater .......................................................................................................................9 2.3.3. Port Jackson ................................................................................................................. 9 2.3.4. Botany Bay.................................................................................................................. 10 2.3.5. Port Hacking .............................................................................................................. 10 2.3.6. Lake Conjola .............................................................................................................. 11 2.3.7. Narrawallee Inlet........................................................................................................ 11 2.3.8. Burrill Lake ................................................................................................................ 11 2.4. Temporal changes in the extent of C. taxifolia ..........................................................................12 2.5. Discussion..................................................................................................................................13 3. DISPERSAL, RECRUITMENT AND GROWTH OF C. TAXIFOLIA IN NSW................................15 3.1. The role of fragments in contributing to spread.........................................................................16 3.1.1. Spatial and temporal patterns of abundance and biomass of C. taxifolia fragments . 16 3.1.2. Preliminary assessment of abundance and biomass of fragments within seagrass beds .................................................................................................................................... 26 3.1.3. The effect of bed structure on the abundance and biomass of C. taxifolia fragments 27 3.2. Persistence and growth of newly established plants ..................................................................32 3.2.1. Stolon extension within and on the edge of established C. taxifolia beds................... 32 3.2.2. Growth of C. taxifolia into Posidonia seagrass beds.................................................. 34 3.2.3. Survivorship of fragments in response to salinity....................................................... 36 3.3. Predation on C. taxifolia ............................................................................................................37 3.4. Discussion..................................................................................................................................38 3.4.1. Asexual Reproduction: fragmentation and stolon extension ...................................... 38 4. VECTORS THAT MAY TRANSFER THE WEED TO NEW LOCATIONS WITHIN NSW...............40 4.1. Patterns of C. taxifolia fragmentation ........................................................................................41 4.1.1. Results.........................................................................................................................42 4.2. Generation of C. taxifolia fragments by boat propellers............................................................46 4.2.1. Methods ...................................................................................................................... 46 4.2.2. Results.........................................................................................................................48 Creese et al. Project No. 35593 ii Contents 4.3. Generation of fragments by anchors.......................................................................................... 51 4.3.1. Methods.......................................................................................................................51 4.3.2. Results .........................................................................................................................51 4.4. The ability of C. taxifolia to survive exposure to air ................................................................. 56 4.4.1. Method ........................................................................................................................56 4.4.2. Results .........................................................................................................................57 4.5. Public awareness of boating activity as a potential vector – a preliminary study...................... 57 4.6. Discussion ................................................................................................................................
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