Improved knowledge of Torres Strait seabed biota and reef habitats Marine and Atmospheric Research M.D.E. Haywood, M. Browne, T. D. Skewes, W.A. Rochester, I.M. McLeod, C.R. Pitcher, D.M. Dennis, J.R. Dunn, S.J. Cheers, T.J. Wassenberg Marine and Tropical Sciences Research Facility Project 1.3.1 Improved knowledge of Torres Strait seabed biota and reef habitats M.D.E. Haywood, M. Browne, T.D. Skewes, W.A. Rochester, I.M. McLeod, C.R. Pitcher, D.M. Dennis, J.R. Dunn, S.J. Cheers, T.J. Wassenberg. CSIRO Marine and Atmospheric Research Marine and Tropical Sciences Research Facility Project 1.3.1 © James Cook University and The University of Queensland. National Library of Australia Cataloguing-in-Publication entry: Author: Haywood, M.D.E (Michael Donald Edmund) 1958- Title: Improved knowledge of Torres Strait seabed biota and reef habitats / authors, M.D.E. Haywood [et al.]. Edition: 1st ed. Publisher: Cleveland, Qld. : CSIRO Marine and Atmospheric Research, 2007. ISBN: 9781921424014 (pbk.) 9781921424038 (CD-ROM) 9781921424021 (pdf) Notes: Bibliography. Subjects: Marine ecology--Torres Strait. Marine biodiversity--Torres Strait. Reefs--Torres Strait--Environmental aspects. Torres Strait--Environmental aspects. Other Authors: CSIRO. Marine and Atmospheric Research. Dewey Number: 577.7476 This report should be cited as: Haywood, M.D.E., Browne, M., Skewes, T., Rochester, W., McLeod, I., Pitcher, R., Dennis, D., Dunn, J., Cheers, S., Wassenberg, T. (2007) Improved knowledge of Torres Strait seabed biota and reef habitats. Marine and Tropical Sciences Research Facility, Cairns (96pp.). Published through the Australian Government’s Marine and Tropical Sciences Research Facility. The Marine and Tropical Sciences Research Facility (MTSRF) is part of the Australian Government’s Commonwealth Environment Research Facilities programme. The MTSRF is represented in North Queensland by the Reef and Rainforest Research Centre Limited (RRRC). The aim of the MTSRF is to ensure the health of North Queensland’s public environmental assets – particularly the Great Barrier Reef and its catchments, tropical rainforests including the Wet Tropics World Heritage Area, and the Torres Strait – through the generation and transfer of world class research and knowledge sharing. This publication is copyright. The Copyright Act 1968 permits fair dealing for study, research, information or educational purposes subject to inclusion of a sufficient acknowledgement of the source. The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government or the Minister for the Environment and Water Resources. While reasonable effort has been made to ensure that the contents of this publication are factually correct, the Commonwealth does not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication. This report is available for download from the Reef and Rainforest Research Centre Limited website: http://www.rrrc.org.au/publications/ February 2007 Marine and Tropical Sciences Research Facility Technical Report No. 1 Contents CONTENTS....................................................................................................................................I LIST OF FIGURES.......................................................................................................................III LIST OF TABLES .........................................................................................................................V 1. ACRONYMS USED IN THIS REPORT ............................................................................VII 2. ACKNOWLEDGEMENTS................................................................................................VIII 3. SUMMARY..........................................................................................................................1 4. BACKGROUND..................................................................................................................2 5. INTER-REEFAL SEABED MAPPING................................................................................2 5.1. Introduction................................................................................................ 2 5.2. Methodology .............................................................................................. 3 5.2.1. Inter-reefal seabed mapping.......................................................... 3 5.2.1.1. Sampling design........................................................................3 5.2.2. Field sampling................................................................................ 4 5.2.2.1. Vessel description .....................................................................4 5.2.2.2. Towed Video Camera ...............................................................5 5.2.2.3. Tasks, Events and Navigation Data Logging............................6 5.2.3. Video data processing ................................................................... 7 5.2.4. Data analysis ................................................................................. 9 5.2.4.1. Physical co-variate data............................................................9 5.2.5. Accounting for aggregation / dispersion....................................... 11 5.2.6. Random forests............................................................................ 12 5.2.7. Transformation in non-parametric estimation .............................. 13 5.3. Results and Discussion .......................................................................... 14 5.3.1. Estimation of spatial distribution of counts................................... 14 5.3.2. Estimation of spatial distribution of cover types........................... 23 5.3.3. Comparison of video biota with that from sled and trawl ............. 27 6. CORAL REEF CHARACTERISATION ............................................................................35 6.1. Introduction.............................................................................................. 35 6.2. Methodology ............................................................................................ 36 6.2.1. Basemap...................................................................................... 36 6.2.2. Reef datasets............................................................................... 36 6.2.3. Survey methods........................................................................... 37 6.2.4. Sample design ............................................................................. 38 6.2.5. Field sampling.............................................................................. 38 6.2.6. Cluster analysis............................................................................ 40 6.2.6.1. Analysis datasets ....................................................................40 i Improved knowledge of biota and habitats 6.2.6.2. Species and habitat clustering ................................................41 6.2.6.3. Habitat-forming species and environmental factors................41 6.2.6.4. Fishes and environmental factors ...........................................42 6.2.7. Gap analysis ................................................................................ 43 6.3. Results...................................................................................................... 43 6.3.1. Physical covariate datasets ......................................................... 43 6.3.2. Maps of survey data..................................................................... 52 6.3.2.1. Substrate maps .......................................................................52 6.3.2.2. Coral growth forms..................................................................60 6.3.2.3. Reef fish distribution................................................................69 6.3.2.4. Holothurian distribution ...........................................................71 6.3.2.5. Seagrass distribution...............................................................73 6.3.3. Clustering the maximum number of samples (a) ......................... 74 6.3.4. Clustering by the maximum number of species (b)...................... 76 6.3.5. Clustering by habitat-forming species (c)..................................... 80 6.3.6. Clustering by habitat attributes (d)............................................... 82 6.3.7. Association between clusters from different analyses ................. 83 6.3.8. Habitat-forming species and fetch ............................................... 84 6.3.9. Habitat-forming species and environmental factors..................... 85 6.3.10. Fishes and environmental factors................................................ 87 6.3.11. Gap Analysis................................................................................ 89 6.4. Discussion................................................................................................ 90 6.4.1. Clustering..................................................................................... 90 6.4.2. Threats......................................................................................... 92 6.4.3. Gap analysis ................................................................................ 92 6.4.4. Identification of areas for future work..........................................