Indirect effects of overfishing on Caribbean reefs: Sponges overgrow reef-building corals
A peer-reviewed article of this Preprint also exists.
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Abstract
Consumer-mediated indirect effects at the community-level are difficult to demonstrate empirically. Here, we show an explicit indirect effect of overfishing on competition between sponges and reef-building corals from surveys of 69 sites across the Caribbean. Removal of sponge-eating angelfishes and parrotfishes resulted in > 3 fold increase in overgrowth of corals by sponges, with coral-sponge contact increasing from 11.0% to 25.6%, and these sponges were mostly species palatable to sponge predators. Palatable species have faster rates of growth or reproduction than defended sponges, which instead make metabolically expensive chemical defenses. On average, overfished sites had lower macroalgal cover, contrary to prevailing assumptions about seaweed control by herbivorous fishes. Coral-sponge competition provides an additional and unambiguous justification for marine protected areas (MPAs) in the Caribbean, where the conceptual model of sponge community ecology and defense trade-offs is notable for the clarity of top-down control and indirect effects across a broad geographic region.
Cite this as
2015. Indirect effects of overfishing on Caribbean reefs: Sponges overgrow reef-building corals. PeerJ PrePrints 3:e836v1 https://doi.org/10.7287/peerj.preprints.836v1note This preprint is not peer-reviewed. You may wish to reference the subsequent peer-reviewed version of this article.
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This is a submission to PeerJ for review.
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Supplemental Information
nMDS plot of survey sites by benthic community structure using square-root transformed occurrences of benthic categories
Sites labeled green are less-fished, and sites labeled blue are overfished. The following benthic categories were used: rock, fire coral, rubble, zoanthid, sponges, other benthos, hard coral, gorgonian, silt, sand, turf, macroalgae, and coralline algae. Prefixes of site names denote the following locations: B, Bahamas; C, Cayman Islands; D, Dominican Republic; E, St. Eustatius; F, Key Largo, FL; J, Jamaica; M, Martinique; O, Bonaire; P, Bocas del Toro, Panama; R, Puerto Rico; S, St. Lucia; U, Curaçao; X, Mexico.
Benthic cover data for all survey sites. (Excel spreadsheet)
Correlation of individual variables with axes 1 and 2 of the nMDS ordination of benthic category occurrence across all survey sites (Fig. S1)
Additional Information
Competing Interests
The authors declare they have no competing interests.
Author Contributions
Tse-Lynn Loh conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper.
Steven E McMurray performed the experiments, reviewed drafts of the paper.
Timothy P Henkel performed the experiments, reviewed drafts of the paper.
Jan Vicente performed the experiments, reviewed drafts of the paper.
Joseph R Pawlik conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, wrote the paper, reviewed drafts of the paper.
Field Study Permissions
The following information was supplied relating to field study approvals (i.e., approving body and any reference numbers):
Fieldwork was conducted under Permit FKNMS-2009-126 in the Florida Keys, National Commission on Aquaculture and Fisheries (Comisión Nacional de Acuacultura y Pesca) Permit DAPA/2/06504/110612/1608 in the Yucatan (Mexico), Department of Marine Resources Permit MAF/LIA/22 (Bahamas Islands), and unnumbered permits or research contracts from St. Lucia, the Cayman Islands, and St. Eustatius.
Funding
Funding for this study was provided by the AMNH Lerner Gray Fund for Marine Research, UNCW Brauer Fellowship and Graduate Student Association Travel Award, NOAA-NURC (NA96RU-0260), NOAA’s Coral Reef Conservation Program and the National Science Foundation (OCE-0550468, 1029515). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.