de Macedo-Soares Luis Carlos Pinto, Garcia Carlos Alberto Eiras, Freire Andrea Santarosa, Muelbert José Henrique
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.
Laboratório de Estudos dos Oceanos e Clima, Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Rio Grande do Sul, Brazil.
PLoS One. 2014 Mar 10;9(3):e91241. doi: 10.1371/journal.pone.0091241. eCollection 2014.
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.
鱼卵和仔鱼是远洋生态系统的重要组成部分，环境因素在决定其分布方面起着重要作用。我们研究了鱼卵和仔鱼丰度的同时纬度和跨陆架梯度，以检验巴西南部陆架鱼类幼体的大规模分布与水体组成相关这一假设。在南半球晚春和初夏季节，于107个站点在南纬21°27′至34°51′之间进行了垂直浮游生物拖网采集。在较深站点从叶绿素最大值深度至海面，或在浅水区从海底上方10米至海面，用圆锥 - 圆柱浮游生物网采集样本。通过CTD/采水器系统获取盐度和温度，该系统还提供用于测定叶绿素a和营养盐浓度的海水。使用指示物种分析法研究水体对幼体鱼类物种的影响，而通过基于距离的冗余分析法分析环境对幼体鱼类物种分布的影响。幼体鱼类物种与特定水体相关：在北部，巴西小沙丁鱼出现在陆架水体中；而在南部，阿根廷鳀栖息在普拉塔羽状水体中。在陆坡处，热带水体的特征是有鬃口光口鱼。同时分析表明跨陆架和纬度梯度对幼体鱼类物种大规模分布都很重要。我们的研究结果表明，鱼卵和仔鱼的组成以及大规模空间分布在纬度和跨陆架梯度上均由水体组成决定。
