Microplastics, Portugal, Commercial fish, Ingestion, Ecotoxicology - methods, Species Specificity, Environmental Monitoring - methods, Estuaries, Polyethylene - analysis, Environmental Exposure - analysis, Water Pollutants, Chemical - analysis, Polypropylenes - analysis, Animals, Gastrointestinal Contents - chemistry, Fishes, Cellulose - analysis, Plastics -...