In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea

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1 Coral Reef Ecology Group (CORE), Leibniz Center for Tropical Marine Ecology (ZMT Bremen), Bremen, Germany
2 Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
3 Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
DOI
10.7287/peerj.preprints.227v1
Published
Accepted
Subject Areas
Ecology, Marine Biology, Zoology, Science and Medical Education
Keywords
Recruitment, Sessile Invertebrates, Nutrient Enrichment, Overfishing, Bioindicator, Settlement, Red Sea, Coral Reefs, Saudi Arabia, Caging Experiments
Copyright
© 2014 Jessen et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
Cite this article
Jessen C, Voolstra CR, Wild C. 2014. In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea. PeerJ PrePrints 2:e227v1

Abstract

In the Central Red Sea, relatively pristine coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing and eutrophication on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. Findings revealed that at the end of the study period invertebrates had almost exclusively colonized shaded tiles, indicating that algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.