title: Large-scale ichthyoplankton and water mass distribution along the South Brazil Shelf.
abstract: Ichthyoplankton is an essential component of pelagic ecosystems, and environmental factors play an important role in determining its distribution. We have investigated simultaneous latitudinal and cross-shelf gradients in ichthyoplankton abundance to test the hypothesis that the large-scale distribution of fish larvae in the South Brazil Shelf is associated with water mass composition. Vertical plankton tows were collected between 21°27' and 34°51'S at 107 stations, in austral late spring and early summer seasons. Samples were taken with a conical-cylindrical plankton net from the depth of chlorophyll maxima to the surface in deep stations, or from 10 m from the bottom to the surface in shallow waters. Salinity and temperature were obtained with a CTD/rosette system, which provided seawater for chlorophyll-a and nutrient concentrations. The influence of water mass on larval fish species was studied using Indicator Species Analysis, whereas environmental effects on the distribution of larval fish species were analyzed by Distance-based Redundancy Analysis. Larval fish species were associated with specific water masses: in the north, Sardinella brasiliensis was found in Shelf Water; whereas in the south, Engraulis anchoita inhabited the Plata Plume Water. At the slope, Tropical Water was characterized by the bristlemouth Cyclothone acclinidens. The concurrent analysis showed the importance of both cross-shelf and latitudinal gradients on the large-scale distribution of larval fish species. Our findings reveal that ichthyoplankton composition and large-scale spatial distribution are determined by water mass composition in both latitudinal and cross-shelf gradients.
authors.affiliation: Laboratório de Crustáceos e Plâncton, Programa de Pós-graduação em Ecologia, Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil; Laboratório de Ecologia do Ictioplâncton, Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: Luis Carlos Pinto
authors.initials: LC
authors.lastname: de Macedo-Soares
authors.affiliation: Laboratório de Estudos dos Oceanos e Clima, Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: Carlos Alberto Eiras
authors.initials: CA
authors.lastname: Garcia
authors.affiliation: Laboratório de Crustáceos e Plâncton, Programa de Pós-graduação em Ecologia, Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil.
authors.forename: Andrea Santarosa
authors.initials: AS
authors.lastname: Freire
authors.affiliation: Laboratório de Ecologia do Ictioplâncton, Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: José Henrique
authors.initials: JH
authors.lastname: Muelbert
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001938:Brazil; D005399:Fishes / Q000502:physiology*; D005843:Geography; D007814:Larva; D009791:Oceanography; D010063:Ovum / Q000254:growth & development; D010933:Plankton / Q000502:physiology*; D054712:Salinity; D012621:Seasons; D013045:Species Specificity; D013696:Temperature; D014867:Water
chemical_list: D014867:Water