Fishing degrades size structure of coral reef fish communities
Author and article information
Abstract
Fishing pressure on coral reef ecosystems has been frequently linked to reductions of large fishes and reef fish biomass. Associated impacts on overall community structure are, however, less clear. In size-structured aquatic ecosystems, fishing impacts are commonly quantified using size spectra, which describe the distribution of individual body sizes within a community. We examined the size spectra of coral reef fish communities at 38 US-affiliated Pacific islands, spanning from near pristine to highly human populated. Reef fish community size spectra slopes ‘steepened’ steadily with increasing human population and proximity to market due to a reduction in the relative biomass of large fishes and an increase in the dominance of small fishes. In contrast, total fish community biomass was substantially lower on inhabited islands than uninhabited ones, regardless of human population density. Comparing the relationship between size spectra and reef fish biomass, we found that on populated islands size spectra steepened linearly with declining biomass, whereas on uninhabited islands size spectra and biomass were unrelated. Size spectra slopes also were steeper in regions of low sea surface temperature but were insensitive to variation in other environmental and geomorphic covariates. In contrast, reef fish biomass was highly sensitive to biophysical conditions, being influenced by oceanic productivity, sea surface temperature, island type, and habitat complexity. Our results suggest that community size structure is more robust than total fish biomass to increasing human presence and that size spectra are reliable indicators of exploitation impacts across regions of different fish community compositions, environmental drivers, and fisheries types. Size-based approaches that link directly to functional properties of fish communities, and are relatively insensitive to abiotic variation across biogeographic regions, offer great potential for developing our understanding of fishing impacts in coral reef ecosystems.
Cite this as
2016. Fishing degrades size structure of coral reef fish communities. PeerJ Preprints 4:e2118v1 https://doi.org/10.7287/peerj.preprints.2118v1Author comment
This is a preprint of a manuscript currently in review at Global Change Biology.
Sections
Supplemental Information
Table S1. Covariate estimates for CREP reef areas
Table S2. Reef areas surveyed in the CREP dataset
Table S3. Parameter estimates and model fit for top size spectra model set (∆AICc < 7)
Table S4. Parameter estimates and model fit for top biomass model set (∆AICc < 7)
Table S5. Parameter estimates and model fit for top length spectra model set (∆AICc < 7)
Additional Information
Competing Interests
The authors declare that they have no competing interests.
Author Contributions
James PW Robinson conceived and designed the experiments, performed the experiments, analyzed the data, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper.
Ivor D Williams reviewed drafts of the paper.
Andrew M Edwards reviewed drafts of the paper.
Jana McPherson wrote the paper, reviewed drafts of the paper.
Lauren Yeager wrote the paper, reviewed drafts of the paper.
Laurent Vigliola reviewed drafts of the paper.
Russell E Brainard reviewed drafts of the paper.
Julia K Baum conceived and designed the experiments, wrote the paper, reviewed drafts of the paper.
Data Deposition
The following information was supplied regarding data availability:
https://github.com/baumlab/robinson-reefs-spectra
Funding
Data on coral reef fish communities was collected by the NOAA Pacific Islands Fisheries Science Center’s Coral Reef Ecosystem Program. Funding for surveys and to support program operation was provided by NOAA’s Coral Reef Conservation Program (http://coralreef.noaa.gov). JPWR was supported by funding from The Leverhulme Trust and the University of Victoria, JMM was supported by an NSERC postdoctoral fellowship, LAY was supported by a National Socio-Environmental Synthesis Center (SESYNC) postdoctoral fellowship funded by the National Science Foundation (DBI-1052875), and JKB acknowledges support from a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant and from an Alfred P. Sloan Research Fellowship in Ocean Science. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
