The Occurrence and Amount of Microplastics Ingested By Fishes in the Watersheds of the Gulf of Mexico

Ingestion of microplastics by freshwater fishes could be an emerging environmental crisis because of the proliferation of plastic pollution in aquatic environments.  Microplastics in marine ecosystems is well documented, however only one study has reported percent occurrence of microplastics (12%) in the digestive system of freshwater fishes.  Purposes of this study were to quantify occurrences and types of microplastics ingested by fishes within the western freshwater drainages of the Gulf Mexico and an estuary of the Gulf of Mexico. 535 fishes were examined in this study, of which 8% in freshwater fishes and 10% in marine fishes had microplastic in their gut tract. Plastic types included polyester, polystyrene, polypropylene, acrylate, and nylon.  Percent occurrence of microplastics ingested by fishes in non-urbanized streams (5%) was less than that of one urbanized streams (Neches River; 29%).  Percent occurrence by habitat (i.e., benthic, pelagic) and trophic guilds (herbivore/omnivore, invertivore, carnivore) were similar.  Occurrences of microplastics in the fishes pose several environmental concerns. For fish health, microplastics absorb toxins and can be passed through the digestive system, into the circulatory system, and accumulate in tissue.  Long-term effects are unknown for the fish or the effects on human consumers.