A comparative study between fished and protected inter-reefal shoal habitats and their fish communities on the Great Barrier Reef Report on ongoing monitoring off Townsville and initial surveys near Cardwell and Cairns, North Queensland Peter Speare and Marcus Stowar Australian Institute of Marine Science Supported by the Australian Government’s Marine and Tropical Sciences Research Facility Project 4.8.2 Effects of the Great Barrier Reef Zoning Plan on inshore habitats and biodiversity: Shoals © Australian Institute of Marine Science National Library of Australia Cataloguing-in-Publication entry: Author: Speare, Peter. Title: A comparative study between fished and protected inter-reefal shoal habitats and their fish communities on the Great Barrier Reef : report on ongoing monitoring off Townsville and initial surveys near Cardwell and Cairns, North Queensland / Peter Speare, Marcus Stowar. ISBN: 9781921359040 (pdf) Notes: Bibliography. Subjects: Fish surveys—Queensland—Great Barrier Reef. Fish populations—Queensland—Great Barrier Reef. Fishes—Habitat—Queensland—Great Barrier Reef. Other Authors/Contributors: Stowar, Marcus, 1975- Reef and Rainforest Research Centre. Dewey Number: 597.009943 This report should be cited as: Speare, P. and Stowar, M. (2008) A comparative study between fished and protected inter-reefal shoal habitats and their fish communities on the Great Barrier Reef. Report on ongoing monitoring off Townsville and initial surveys near Cardwell and Cairns, North Queensland. Report to the Marine and Tropical Sciences Research Facility. Reef and Rainforest Research Centre Limited, Cairns (60pp.). Published by the Reef and Rainforest Research Centre on behalf of 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, Water, Heritage and The Arts. 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/research_reports.html Published in April 2008. Seasonality on Magnetic Shoals: First Baseline Surveys Contents List of Figures........................................................................................................................... ii List of Tables............................................................................................................................iii Acronyms Used In This Report ................................................................................................iii Abstract ....................................................................................................................................1 1. Introduction .....................................................................................................................3 2. Objectives ........................................................................................................................3 3. Methods............................................................................................................................4 3.1 Study Sites.................................................................................................................4 3.2 Sampling....................................................................................................................5 3.3 Data Analysis.............................................................................................................7 4. Results .............................................................................................................................8 a. Townsville...................................................................................................................8 b. Cardwell...................................................................................................................17 c. Cairns.......................................................................................................................25 5. References .....................................................................................................................33 Appendix 1: Acoustic Images of Study Sites ...................................................................35 Townsville........................................................................................................................35 Cardwell ..........................................................................................................................39 Cairns ..............................................................................................................................42 Appendix 2: Classification Information.............................................................................48 Appendix 3: BRUVS Operational Data ..............................................................................51 i Speare and Stowar List of Figures Figure a1: Townsville study sites from Halifax and Bowling Green Bays .............................................8 Figure a2: The relative contributions of the primary substrate (A) and epibenthic (B) classes on Magnetic Shoal (A and B) and adjacent blue sites (C and D) ........................................9 Figure a3: The mean number of species (±1SE) recorded from structurally complex (closed bars) and adjacent rubble sand (open bars) habitats in green and blue zones off Townsville ..........................................................................................................................10 Figure a4: Mean number of species (±1SE) on the structurally complex habitats (closed bars) and the surrounding sand/rubble phototrophic habitats (open bars) over the four sampling periods at each of the three green (left-hand side) and three blue (right- hand side) sites..................................................................................................................11 Figure a5: The mean relative abundance (±1SE) of species correlated with the two principal habitats on shoal sites in the Townsville region. Closed bars = complex epibenthic filter feeding communities; open bars = low diversity phototrophic epibenthic communities.......................................................................................................................12 Figure a6: Biplot of transformed (4th root, row standardised) fish relative abundances over all sites and sampling periods. Vectors representing the correlation of species with the primary groupings are displayed along with the relative positions of sites, habitats and zones...........................................................................................................................13 Figure a7: Biplot of transformed (4th root, row standardised) targeted fish relative abundances over all sites and sampling periods. Vectors representing the correlation of species with the primary groupings are displayed along with the relative positions of sites, habitats and zones.............................................................................................................14 Figure a8: Mean relative abundance (±1SE) of species displaying temporal changes over the sampling period between July 2006 and March 2007 in the green zone at Magnetic Shoals (closed bars) and adjacent blue zones (open bars) ..............................................15 Figure b1: Cardwell study sites in Rockingham Bay...........................................................................17 Figure b2: The relative contributions of the primary substrate (A) and epibenthic (B) classes on the sites at Brook Shoal and Eva Rock. Note, Forty Foot Rock was not surveyed..........18 Figure b3: The mean number of species (±1SE) recorded from BRUVS sets on Brook Shoal, Eva Rock and Forty Foot Rock. (a) Muddy sand and rocky habitats combined; (b) closed bars = hard bottom; open bars = soft bottom....................................................19 Figure b4: Canonical analysis of BRUVS sets made on rocky (left-hand side) and muddy sand (right-hand side) substrates at Brook Shoal (B), Eva Rock (E) and Forty Foot Rock (F) clearly distinguished (p < 0.05) fish assemblages associated with the two habitat types. This analysis also highlighted the more variable fish assemblages associated with the muddy sand