Discrimination of hydrologic variations for spatial distribution of fish assemblage in a large subtropical temperate river

This study examines the effects of the flow and flood pulses on spatialdispersion of fish assemblages in the floodplain of the Paraná River in Argentina. Wetested the hypothesis that high water levels and greater lateral connectivity promotefish dispersal and spatial homogenization of assemblage structure. We sampled foursites during different phases of the annual hydrologic cycle from 2010 to 2016. Watersurface in the area was estimated during each phase. We computed multivariatestatistics and estimates of ß-diversity to analyze assemblage variations in relation tohydrological phases. Three hydrological phases were defined: low flow pulses (waterlevels between 2.3 and 3.2, approximately 10% of the floodplain covered by water),high flow pulses(between 3.2 and 4.5, from 11 to 84%), and floods (> 4.5 m, morethan 84%). Although difference between high flow pulses and flood was notsignificant, ß-diversity values for these stages were higher than for low flow pulses.This suggests that floods and high flow pulses increase the spatial variability of fishassemblages, whereas homogenization processes occur later during low flowperiods. This work provides further knowledge about the flood homogenization effectin a large unregulated floodplain where lateral connectivity still plays a significant roleon ecological structuring processes.Fil: Espínola, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Abrial, Elie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Rabuffetti, Ana Pia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Simoes Da Silva, Nadson Ressyé. Universidade Federal Do Sul Da Bahia. Centro de Formação Em Ciências Ambientais.; BrasilFil: Amsler, Mario Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Blettler, Martin Cesar Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Eurich, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Paira, Aldo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Intake of microplastics by commercial fish: A Bayesian approach

The disordered growth of large cities around water bodies causes environmental damage due to discarded plastics and microplastics (MPs) that aquatic organisms can ingest. This study analyzed the occurrence, type, and abundance of MPs in the gastrointestinal contents of four species of commercial fish (120 total specimens), namely, Brazilian mojarra (Eugerres brasilianus) and mullets (Mugil curema, Mugil curvidens, and Mugil liza), obtained in Porto Seguro in Bahia, Brazil, between March and May 2019. A priori probability distributions were generated using a Bayesian approach and simulations to assess MP intake based on varying exposure amounts (θ = 0.2, θ = 0.5, and θ = 0.8). E. brasilianus (53.33%) and Mugil spp. (41.66%) were contaminated with some types of MPs. Black, blue, and green MPs dominated in the extracted samples, and most measured 1.0 mm in length or smaller. The dominant polymers identified using Fourier transform infrared spectroscopy (FTIR) were polyester, polypropylene, semi-synthetic rayon fiber, and polyamide 6 (nylon). The a posteriori probabilities of more than half the E. brasilianus and Mugil spp. ingesting MPs were 0.336 and 0.008, respectively, indicating that E. brasilianus is much more likely to ingest MPs. These simulations can be useful tools for assessing the environmental quality and local anthropic impact of MP ingestion by fish populations.Fil: Nunes, Lucélia S.. Universidade Estadual de Santa Cruz; BrasilFil: Silva, Allison G.. Instituto Federal de Educação, Ciência e Tecnologia da Bahia; BrasilFil: Espínola, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Blettler, Martin Cesar Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Simoes Da Silva, Nadson Ressyé. Universidade Federal do Sul da Bahia; Brasi