Microhabitat use of juvenile coral reef fish in Palau

While relationships between adult fish density and structural habitat features are well established, relatively little is known about the habitat associations of juvenile reef fish. In a reserve system in Palau, we quantified microhabitat association with juvenile reef fish community structure, and determined the influence of foraging space, predator size and confamilial attraction on juvenile and adult pomacentrid abundance. Habitat structure and juvenile reef fish communities differed significantly among microhabitats with one exception: no difference was found between foliose and consolidated rubble microhabitats. Overall, pomacentrids characterised the juvenile community structure of each microhabitat. The abundance of early juvenile pomacentrids is simultaneously determined by microhabitat structure and predator size, with little evidence for settlement selection near adults. The results also suggest that the influence of habitat structure become weaker with ontogeny which in part, drives large predators to negatively influence the abundance of adult pomacentrids. The results have important implications on management, specifically in prioritizing areas for protection, and in modeling the impacts of habitat loss on reef fish communities

Location of reefs sites surveyed on the northernmost section of the GBR.

<p>The legend on the top left indicates the color code to reference each reef by shelf location and management status. Sources: GBRMPA datasets: Great Barrier Reef Features (Version 1.2), Special Management Areas (v1.0), Marine Bioregions of the Great Barrier Reef (Reef) (v2.0). Retrieved from <a href="http://www.gbrmpa.gov.au/geoportal" target="_blank">http://www.gbrmpa.gov.au/geoportal</a>. Map created using ArcGIS® software by Esri.</p

Benthic components that made the greatest contribution to dissimilarity among zones.

<p>Mean <b>%</b> cover (± SE) of the benthic components identified by SIMPER analyses as major contributors to the dissimilarity in benthic community structure among zones (fished = blue, no-take = green, no-entry = pink) in each sub-region (a-f). Significant differences between reserves (i.e. no-take vs no-entry) were only found in northern mid-shelf reefs and outer-central reefs. Sedim/turf = sediment-laden turfs.</p

Characterization of surveyed reef sites.

<p>Characterization of surveyed reef sites.</p

Principle Coordinate Analysis (PCO) of benthic cover.

<p>Ordination plots show (a) reef sites along the first two axes based on shelf position, (b) overlay of vectors based on Spearman correlations. Strongest correlations (> 0.5) shown in red. Cover data were square-root transformed for analyses.</p

Principle Coordinate Analysis (PCO) of the assemblage structure of non-fished species.

<p>Plots show (a) ordination of reef sites along PCO1indicating shelf position, (b) within reef variability along PCO2 (separation of replicate sites of same reef), (c) species with strongest associations (Spearman >0.5) to PCO2: pomacentrids are shown in black, (d) Observer’s identity associated with PCO2 variability, and (e) variation in biomass of <i>P</i>. <i>leopardus</i> along PCO2. Biomass was log+1 transformed for analyses.</p

Summary of linear mixed models testing zoning and habitat effects on fish biomass.

<p>Summary of linear mixed models testing zoning and habitat effects on fish biomass.</p