Evidences of microplastics in diverse fish species off the Western Coast of Pacific Ocean, Mexico

Abstract We examined the presence of microplastics (MPs) in the gut contents of six fish species (Calamus brachysomus, Paralabrax maculatofasciatus, Eucinostomus dowii, Balistes polylepis, Achirus mazatlanus and Mugil curema) procured from Magdalena bay, Pacific Coast, Mexico. A total of 64 MPs were extracted from 87 individual samples, amongst which E. dowii (30 particles) and P. maculatofasciatus (27 particles) species presented the highest number of MPs. Of these, the majority of the MPs were fibrous filaments mainly of size 100 μm. The colour distribution was white-transparent (43%) and blue (36%). SEM imaging revealed the impact of mechanical weathering and disintegration through the presence of angular and irregular edges in the fibers. Likewise, strong carbon and oxygen peaks in the EDX spectra verified the fibers to be plastics. Differences in the ingestion of MPs among species are mainly due to species-specific physiognomies, habitat, feeding strategies and the availability of plastics. The present study contributes with a baseline data and a first assessment of microplastics debris ingested by fishes of Magdalena bay, Mexico.