Avaliação da presença de microplásticos no trato grastrointestinal do peixe-rei (Atherinella brasiliensis) em praias da região de Ubatuba, SP, Brasil

Abstract

The beaches of the municipality of Ubatuba are known for their diverse fauna. One of the most abundant species of the ichthyofauna in the region is the beach silverside (Atherinella brasiliensis), object of this study. We studied the degree of contamination by microplastics through the analysis of the gastrointestinal tract of A. brasiliensis specimens. Comparative analyses were made in two beaches with different hydrodynamics. The beaches chosen for this study are Perequê-Açú and Barra da Seca, the former being divided into two sampling areas: one calmer and another more energetic. Each beach was sampled twice, one during winter and the other during summer. The collected fish were measured, their gastrointestinal content was extracted, and the microplastics, if present, were classified according to colour, shape, size, and quantity. Simultaneously, measurements of environmental parameters and collection of water and sediment samples were made to correlate the presence of microplastic in the water and sediment, as well as to determine the influence of abiotic factors such as water temperature and salinity and sediment granulometry. The degree of contamination in the individuals was observed and considered high (~40% of the individuals analysed), with the predominant synthetic polymers being blue and transparent of the fiber type. There was a higher consumption of microplastics in the summer at Barra-Seca (45%) and in the winter at Perequê Calma (50%), and a similarity of microplastics in the water samples in both periods. The variation of microplastics in the water and in the gastrointestinal tract of fish was similar, which demonstrates the importance of including data of the biotic environment, as well as the physical environment (water and sediment) in studies such as this.