Macroorganisms fouled in marine anthropogenic litter (rafting) arround a tropical bay in the Southwest Atlantic

The presence of floating marine anthropogenic litter in marine environments increase the possibility of transportation of fouling organisms using these substrates as a vector, mainly for those species with close affinities to artificial substrates. The objectives were to qualitatively and quantitatively report anthropogenic litter and its associated fouling groups arround Ilha Grande Bay (IGB). Litter was collected, classified and examined for the presence of fouling organisms on beaches located at two different levels of wave exposure during rainy and dry seasons. The types of litter do not differ among beaches, and the highest density and cover of fouling were reported on exposed beaches due the currents, winds, and storm waves. Bryozoans, barnacles, polychaetes, and mollusks were the most frequent fouling groups observed in litter and represents a potential vector for the dispersion of species in the IGB and adjacent coastal areas. •A new methodology was developed to assess the percentage of biofouling coverage.•The highest density and cover of biofouling were reported on exposed beaches.•Bryozoans, barnacles, polychaetes, and mollusks were the main biofouling groups.•Bryozoans were mostly found in plastic.•The species found in the region are considered invasive and cryptogenic.