Strong hydrodynamic drivers of coral reef fish biodiversity on submerged pinnacle coral reefs

Galbraith, Gemma F., Cresswell, Benjamin J., McCormick, Mark I., and Jones, Geoffrey P. (2023) Strong hydrodynamic drivers of coral reef fish biodiversity on submerged pinnacle coral reefs. Limnology and Oceanography, 68 (11). pp. 2415-2430.

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Hydrodynamic processes are important in all marine environments and on coral reefs drive patterns of habitat zonation, community structure, and biodiversity. Abrupt geomorphological features like pinnacles and seamounts often possess distinct localized currents and these habitats are also often characterized by high abundance and biomass of fishes. However, differences in fish community structure between pinnacles and emergent reefs, and their key drivers are poorly understood. In this study, we compared fish communities among emergent fringing and offshore coral reefs, and submerged pinnacle reefs in Papua New Guinea. Submerged pinnacles possessed higher fish biomass, abundance, and species richness than both fringing and offshore emergent reefs. We collected in-situ current speed and temperature data over a full year at each reef and used random forest analysis to investigate the relative influence of hydrodynamics compared to other well-established drivers of reef fish biodiversity, including habitat and biogeographic factors. Environmental variables explained 70%, 52%, and 5% of variability in models for species richness, abundance and biomass respectively. In all models, average current speed, current speed variability, and reef area were consistently among the most influential variables. Models examining relationships between fish biodiversity metrics and current speed did not yield conclusive results but did highlight the association of distinct hydrodynamic regimes on pinnacles with high fish richness, abundance, and biomass. Our study highlights the strong influence of reef-scale hydrodynamics on fish biodiversity and demonstrates the ecological value of small, submerged coral reefs, which are globally numerous yet remain understudied in coral reef ecology.

Item ID: 80480
Item Type: Article (Research - C1)
ISSN: 1939-5590
Keywords: Submerged reefs, pinnacles, seamounts, hydrodynamics, reef fishes
Copyright Information: © 2023 The Authors. Limnology and Oceanography published by Wiley Periodicals LLC on behalf of Association for the Sciences of Limnology and Oceanography. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Funders: Australian Research Council (ARC)
Projects and Grants: ARC Discovery Grant DP190103056, ARC Centre of Excellence for Coral Reef Studies
Date Deposited: 03 Oct 2023 00:15
FoR Codes: 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 45%
37 EARTH SCIENCES > 3708 Oceanography > 370801 Biological oceanography @ 45%
37 EARTH SCIENCES > 3705 Geology > 370504 Marine geoscience @ 10%
SEO Codes: 18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180504 Marine biodiversity @ 40%
18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180506 Oceanic processes (excl. in the Antarctic and Southern Ocean) @ 20%
28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280111 Expanding knowledge in the environmental sciences @ 40%
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