Extreme Weather Incident Response Post Tropical Cyclone Ita assessment of intertidal seagrass status in dugong and green turtle feeding grounds ‐ Jeannie River to Cape Bedford (Cape York) Len McKenzie, Rob Coles, Louise Johns & Jessica Leech Report No. 14/25 May 2014 i Information should be cited as: McKenzie, LJ., Coles, R., Johns, L. and Leech, J. 2014, ‘Post Tropical Cyclone Ita assessment of intertidal seagrass status in dugong and green turtle feeding grounds ‐ Jeannie River to Cape Bedford (Cape York)’. Centre for Tropical Water & Aquatic Ecosystem Research (TropWATER) report 14/25. Cairns, James Cook University, Cairns. 20 pp. For further information contact: Len McKenzie Centre for Tropical Water & Aquatic Ecosystem Research (TropWATER) James Cook University [email protected] PO Box 6811 Cairns QLD 4870 This publication has been compiled by the Centre for Tropical Water & Aquatic Ecosystem Research (TropWATER), James Cook University. Email: [email protected] Web: www.jcu.edu.au/tropwater/ © James Cook University, 2014. Except as permitted by the Copyright Act 1968, no part of the work may in any form or by any electronic, mechanical, photocopying, recording, or any other means be reproduced, stored in a retrieval system or be broadcast or transmitted without the prior written permission of TropWATER. The information contained herein is subject to change without notice. The copyright owner shall not be liable for technical or other errors or omissions contained herein. The reader/user accepts all risks and responsibility for losses, damages, costs and other consequences resulting directly or indirectly from using this information. Acknowledgments: This project was funded by the Great Barrier Reef Marine Park Authority (GBRMPA) and the Centre for Tropical Water & Aquatic Ecosystem Research (TropWATER), James Cook University, Cairns. We thank the Traditional Owners of the Sea Countries we visited to conduct this assessment. ii Post TC Ita seagrass assessment - – 2014 TropWATER 14/25 Table of Contents EXECUTIVE SUMMARY ................................................................................................................................5 OBJECTIVE:............................................................................................................................................... 6 INTRODUCTION & BACKGROUND ............................................................................................................... 6 Background on the seagrass resources from Cape Bedford to Jeannie River ......................................... 7 METHODOLOGY ........................................................................................................................................ 8 Survey strategy and Data Collection .................................................................................................... 8 RESULTS & DISCUSSION .............................................................................................................................. 9 Jeannie River to Starcke River .............................................................................................................. 9 Starcke River to Lookout Point ........................................................................................................... 12 Lookout Point to Cape Flattery........................................................................................................... 14 Cape Flattery to Cape Bedford ........................................................................................................... 18 CONCLUSIONS & RECOMMENDATIONS .................................................................................................... 19 REFERENCES ............................................................................................................................................ 20 3 Post TC Ita seagrass assessment - – 2014 TropWATER 14/25 List of Figures Figure 1. Track of Tropical Cyclone Ita....................................................................................................................6 Figure 2. Helicopter flight path from Jeannie River to Cape Bedford, 30th April 2014..........................................8 Figure 3. Intertidal banks immediately south of the Jeannie River with Halodule univervis..................................9 Figure 4. Halodule uninervis and Halophila ovalis meadow on southern banks of Jeannie River mouth ............10 Figure 5. Mangrove leaves in wrack along shoreline (little or no seagrass present in wrack) and on the northern bank of the Starcke River mouth .........................................................................................................10 Figure 6. Intertidal sand banks with Halodule uninervis and intact mangrove fringe ..........................................10 Figure 7. Intertidal banks with Halodule uninervis and intact mangrove fringe...................................................11 Figure 8. Large intertidal banks with extensive dugong grazing scars throughout the Halodule uninervis/Halophila ovalis meadows...................................................................................................11 Figure 9. Abundant dugong grazing trails throughout Halodule uninervis/Halophila ovalis meadows ...............11 Figure 10. Abundant dugong grazing trails in Halodule uninervis meadows across intertidal sand banks and adjacent to mangrove fringe ...............................................................................................................11 Figure 11. Low cover of Halophila ovalis within coral rubble...............................................................................12 Figure 12. Extensive dugong grazing scars in seagrass meadows, between Starcke River and Lookout Point....12 Figure 13. Halophila ovalis in gravel/coarse sand substrate ................................................................................12 Figure 14. Dugong grazing scars in the Halodule uninervis/Halophila ovalis meadows located on the large intertidal sand banks ...........................................................................................................................13 Figure 15. Intact mangroves along seaward fringe ..............................................................................................13 Figure 17. Extensive dugong grazing scars throughout Halodule uninervis/Halophila ovalis meadows..............13 Figure 18. Melaleuca adjacent to dunes showing extensive defoliation (top) and Rhizophora behind the shoreline with defoliation from damaging winds (bottom), 3km north of Lookout Point..................14 Figure 19. Large intertidal sand banks with sparse covering of Halodule uninervis, immediately north of Lookout Point.......................................................................................................................................14 Figure 20. South east facing beaches with no seagrass........................................................................................15 Figure 21. Meadows of Halodule uninervis and Halophila ovalis on the intertidal bank adjacent to Crystal Creek .............................................................................................................................................................15 Figure 22. Dense Halodule uninervis meadow with sheltered coastal lagoon, with dugong grazing scars and sandfish................................................................................................................................................16 Figure 23. Meadows of Halodule uninervis and Halophila ovalis on the large intertidal banks, with dugong grazing scars, near Blackwater Creek ..................................................................................................16 Figure 24. Meadows of Halodule uninervis and Halophila ovalis with dugong grazing scars on the large intertidal banks, 4‐6km north of Cape Flattery ...................................................................................16 Figure 25. Blowouts and dugong grazing scars within Halodule uninervis/Halophila ovalis meadow 2‐3km north of Cape Flattery township....................................................................................................................17 Figure 26. Undamaged seedlings at seaward edge of Rhizophora forest, Cape Flattery .....................................17 Figure 27. Intact mangrove forests immediately north of Cape Flattery .............................................................18 Figure 28. Intact seagrass meadow, Elim Beach...................................................................................................18 Figure 29. Seagrass meadow in shallow coastal lagoon, Elim Beach. NB: defoliation in trees on top of ridge but no damage to foreshore mangroves ‐ indicating damaging winds from the west (from the land).....18 Figure 30. Dense Halodule uninervis meadow on rippled sand banks adjacent to McIvor River mouth .............19 Figure 31. Seagrass meadow in shallow coastal lagoon, Elim Beach, and wide intertidal banks, looking east toward Cape Bedford...........................................................................................................................19 4 Post TC Ita seagrass assessment - – 2014 TropWATER 14/25 EXECUTIVE SUMMARY Tropical Cyclone Ita TC (Category 4) impacted the north Queensland coast in early April 2014, making landfall at about 2200hrs on the evening of Friday April 11th near Cape Flattery.