Microplastic contamination in tropical fishes: An assessment of different feeding habits

Marine ecosystems are reported to be contaminated by microplastics (MPs) (< 5 mm); however, the ecological mechanisms involved in the ingestion of debris by marine organisms are relatively unknown. By developing and optimising an appropriate protocol of gut digestion for fish species, this study explores a tropical estuarine environment to unriddle the processes responsible for the different ingestion rates of plastic debris. A total of 82 fishes with different feeding habits were analysed, Centropomus undecimalis (n = 30; Piscivore), Bairdiella ronchus (n = 21; Zoobenthivore) and Gobionellus stomatus (n = 31; Detritivore). The microplastic ingestion varied with the feeding strategy; C. undecimalis, the predator, was the most contaminated species. Overall, most MPs were fibres (47%), followed by pellets (40%) and fragments (13%), although these proportions varied among species. A high level of contamination was found in the Estuarine Complex of Santa Cruz Channel, Northeast of Brazil, with many potential input sources of MPs to the estuary, which likely accumulates in the sediment and water column, with unknown consequences for human health.