Abundance and Distribution of Microplastics in Fish by Trophic Level in Kupang Bay, Indonesia

Kupang Bay is home to a diverse array of fish species and other vital marine resources. However, increasing human activities—including industrial development, fisheries, and tourism—have contributed to elevated levels of microplastic pollution. This study aimed to assess the abundance and distribution of microplastics in fish, categorized by trophic levels (herbivores and carnivores), as well as by the shape, size, and color of microplastics found in different fish organs: the gastrointestinal tract, gills, and muscle, in the waters of Kupang Bay. The research process involved sampling fish from three different locations, identifying microplastics using a microscope, describing the characteristics of identified microplastics, and analyzing their abundance in the fish samples. Microplastics were detected in all organ types of both herbivorous and carnivorous fish. The microplastics appeared in various forms, including fibers, fragments, films, and pellets. Among these, the most dominant type was blue-colored fibers measuring less than 0.25mm. Carnivorous fish exhibited the highest abundance of microplastics, particularly fibers found in the gastrointestinal tract. Notably, there were differences in microplastic abundance across the three sampling sites. However, no significant difference was observed in the average microplastic abundance between carnivorous and herbivorous fish. The presence of microplastics in multiple organs of fish across different trophic levels poses a potential threat to marine biodiversity and fisheries sustainability. Furthermore, the risk of microplastic accumulation through the food chain could have implications for human health.