title: Trophic segregation of a fish assemblage along lateral depth gradients in a subtropical coastal lagoon revealed by stable isotope analyses.
abstract: Stable isotopes were used to evaluate the hypothesis that fish assemblages occurring in shallow and deep areas of a large coastal lagoon are structured in partially segregated trophic modules with consumers showing contrasting reliance on benthic or pelagic food sources. The results revealed that fishes in deep areas were mainly dependent on particulate organic matter in the sediment (SOM), whereas emergent macrophytes were as important as SOM to fish consumers in shallow areas. Conceptual trophic diagrams depicting relationships among basal food sources and consumers in different regions of the lagoon highlighted the greater use of multiple basal food sources by more feeding mode functional guilds in shallow water compared with the use of predominantly benthic resources (SOM) in deep areas. The findings appear to corroborate the initial hypothesis and offer complementary perspectives in understanding the role of spatial ecology in structuring coastal ecosystem function and productivity.
authors.affiliation: Ichthyology Laboratory, Institute of Oceanography, Federal University of Rio Grande (FURG), Av. Itália, km 08, Carreiros, Rio Grande, RS, 96.203-900, Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Mont'Alverne
authors.affiliation: Ichthyology Laboratory, Institute of Oceanography, Federal University of Rio Grande (FURG), Av. Itália, km 08, Carreiros, Rio Grande, RS, 96.203-900, Brazil.
authors.forename: P E R
authors.initials: PE
authors.lastname: Pereyra
authors.affiliation: Ichthyology Laboratory, Institute of Oceanography, Federal University of Rio Grande (FURG), Av. Itália, km 08, Carreiros, Rio Grande, RS, 96.203-900, Brazil.
authors.forename: A M
authors.initials: AM
authors.lastname: Garcia
mesh_terms: D000818:Animals; D001938:Brazil; D002247:Carbon Isotopes / Q000032:analysis; D017753:Ecosystem; D005399:Fishes; D020387:Food Chain; D009587:Nitrogen Isotopes / Q000032:analysis
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes
keywords: Patos Lagoon estuary; benthic subsidy; depth compartmentalization; trophic modules