Widespread microplastic ingestion in Colombian Caribbean marine fish: Trophic influence, spatial-temporal trends, and polymer composition

The ingestion of microplastics (MPs) by marine fish is increasingly frequent due to the ubiquity of plastic pollution in marine environments. This study evaluated the prevalence, characteristics, and possible sources of MPs in the gastrointestinal tract of three ecologically and commercially important fish species (Caranx crysos, Euthynnus alletteratus, and Pterois volitans) from the Continental Caribbean (CC) Sea in the Department of Atlántico and the Insular Caribbean (IC) Sea on the San Andrés Island of Colombia. A high prevalence of MPs ingestion was found in all species (82.6 % in CC; 84.6 % in IC), with spatial and temporal variability in MPs abundance. Higher concentrations were found in the continental area and during the wet season. Fibers and fragments were the predominant shapes, with blue, black, and gray being the most common colors. Chemical characterization by attenuated total reflectance Fourier transform infrared microspectroscope (μATR-FTIR) revealed different polymer types, including polyamide (PA), polyethylene terephthalate (PET), and synthetic and natural polymer blends. Trophic ecology analysis showed that species feeding on smaller fish and bottom invertebrates had higher MPs burdens. However, MPs ingestion was not consistently associated with fish condition factor. The widespread presence of different polymer types, including emerging threats from synthetic-natural polymer blends and sizes smaller than 50 μm, underscores the pervasive nature of plastic pollution in this region and its potential ecological implications, particularly for species at higher trophic levels and overall marine ecosystem health.