Deep-reef fish communities of the Great Barrier Reef shelf-break: trophic structure and habitat associations

Sih, Tiffany L., Daniell, James J., Bridge, Thomas C. L., Beaman, Robin J., Cappo, Mike, and Kingsford, Michael J. (2019) Deep-reef fish communities of the Great Barrier Reef shelf-break: trophic structure and habitat associations. Diversity, 11. 26.

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The ecology of habitats along the Great Barrier Reef (GBR) shelf-break has rarely been investigated. Thus, there is little understanding of how associated fishes interact with deeper environments. We examined relationships between deep-reef fish communities and benthic habitat structure. We sampled 48 sites over a large depth gradient (54–260 m) in the central GBR using Baited Remote Underwater Video Stations and multibeam sonar. Fish community composition differed both among multiple shelf-break reefs and habitats within reefs. Epibenthic cover decreased with depth. Deep epibenthic cover included sponges, corals, and macro-algae, with macro-algae present to 194 m. Structural complexity decreased with depth, with more calcified reef, boulders, and bedrock in shallower depths. Deeper sites were flatter and more homogeneous with softer substratum. Habitats were variable within depth strata and were reflected in different fish assemblages among sites and among locations. Overall, fish trophic groups changed with depth and included generalist and benthic carnivores, piscivores, and planktivores while herbivores were rare below 50 m. While depth influenced where trophic groups occurred, site orientation and habitat morphology determined the composition of trophic groups within depths. Future conservation strategies will need to consider the vulnerability of taxa with narrow distributions and habitat requirements in unique shelf-break environments.

Item ID: 58334
Item Type: Article (Research - C1)
ISSN: 1424-2818
Keywords: deep reefs; shelf-break habitats; BRUVS; multibeam bathymetry; fish-habitat associations; trophic structure
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Copyright Information: © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY 4.0) license
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A version of this publication was included as Chapter 3 of the following PhD thesis: Sih, Tiffany L. (2019) Diving into the deep-end: investigating tropical deep-reef fish assemblages. PhD thesis, James Cook University, which is available Open Access in ResearchOnline@JCU. Please see the Related URLs for access.

Date Deposited: 05 Oct 2019 03:21
FoR Codes: 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 70%
41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410401 Conservation and biodiversity @ 30%
SEO Codes: 96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960507 Ecosystem Assessment and Management of Marine Environments @ 100%
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