Reef fish community structure on coastal islands of the southeastern Brazil: the influence of exposure and benthic cover |
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Authors: | Sergio R Floeter Werther Krohling João Luiz Gasparini Carlos E L Ferreira Ilana R Zalmon |
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Institution: | 1.Laboratório de Ciências Ambientais,Universidade Estadual do Norte Fluminense,Campos dos Goytacazes,Brazil;2.Departamento de Ecologia e Zoologia–CCB,Universidade Federal de Santa Catarina,Floriano′polis,Brazil;3.Departamento de Ecologia e Recursos Naturais,Universidade Federal do Espírito Santo,Vitória,Brazil;4.Departamento de Biologia Marinha,Universidade Federal Fluminense,Niterói,Brazil |
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Abstract: | Patterns of community structure in the marine environment are strongly influenced by population relationships to biotic and
physical gradients. The aim of this work is to explore the relationships of tropical rocky reef fish assemblages to wave exposure
and benthic coverage in a gradient of distance from the coast. The study was conducted on the Guarapari Islands, southeastern
Brazilian coast. Fish were sampled by underwater visual census (166 transects) and benthic cover was estimated with quadrats
(223 replicates). Two main kinds of habitats were found to be derived from the close interrelation between exposure and benthic
coverage: (1) exposed areas subjected to major hydrodynamic forcing, and (2) sheltered or moderately exposed areas. The first
group is associated with mid-water schooling species like planktivorous labrids and Chromis, piscivorous Caranx, as well as gregarious omnivores like Abudefduf and Diplodus. In terms of benthic composition, macroalgae and encrusting calcareous algae prevail in this high-energy habitat. The second
group is characterized by site-attached and reef associated species like territorial pomacentrids, invertebrate feeders such
as Halichoeres poeyi and Chaetodon striatus, and small cryptobenthic fishes (e.g. blenniids and labrisomids). Turf algae, zoanthids and massive corals dominate this
environment. Environmental plasticity is also common with some genera showing high abundances in all habitats (e.g. Holocentrus, Haemulon, Acanthurus). Examples of the coupling of food availability and fish abundance were found. Planktivores, territorial herbivores, macroalgae
browsers and spongivores were positively related with the abundance of their preferred food items along the exposure gradient.
Within-family analyses of Pomacentridae and Labridae showed that niche partitioning is likely occurring and seems to be mediated
by swimming ‘ability’ and associated feeding performance. |
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Keywords: | Rocky shore Wave exposure gradient Feeding behavior Reef fish |
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