The present study was carried out in the lagoon and island systems of Navachiste and Ohuira Sinaloa México. Four samplings were conducted during an annual cycle, at eight sampling sites, during an annual cycle from November 2018 to October 2019., 573 organisms from 6 commercially important fish species were captured and analyzed. The stomachs of each organism captured were analyzed under the stereomicroscopic technique. The results show that four of the six species analyzed presented contamination by microplastics, finding 5 types with sizes that varied from 0.33 to 4.72 mm. nylon was the microplastic with the highest number of occurrences, found in four of the six species observed (Pomadasys macracanthus , Diapterus peruvianus , Cynoscion othonopterus and Lutjanus sp.), with a total of 99 particles. In D. peruvianus in a single organism polyurethane was found with 42 counted fragments, followed by fragments of plastic bags (polyethylene) in P. macracanthus, 14 plastic elements, polyethylene terephthalate (PET) and fragments of polyester fibers were observed on the silver carp. It is suggested that organisms with omnivorous eating habits present a higher degree of susceptibility to the ingestion of microplastics and that predatory organisms acquire plastic pollutants through bioaccumulation processes. The microplastics found are related to fishing activities, so it is suggested to work with the communities of the fishing places, to strengthen the knowledge bases around this environmental problems.
Key words: Microplastics, fish, sustainable management, Northwest México.