Microplastics (MP) pollution has received increased attention over the last few years. However, while the number of studies documentating the ingestion of microplastics by fish has increased, fewer studies have addressed the toxicological effects derived from the ingestion of these small items in wild conditions. Here, MP contamination and effect biomarkers were investigated in three commercially important fish species from the North East Atlantic Ocean. From the 150 analysed fish (50 per species), 49 % had MP. In fish from the 3 species, MP in the gastrointestinal tract, gills and dorsal muscle were found. Fish with MP had significantly (p ≤ 0.05) higher lipid peroxidation levels in the brain, gills and dorsal muscle, and increased brain acetylcholinesterase activity than fish where no MP were found. These results suggest lipid oxidative damage in gills and muscle, and neurotoxicity through lipid oxidative damage and acetylcholinesterase induction in relation to MP and/or MP-associated chemicals exposure. From the 150 fish analysed, 32 % had MP in dorsal muscle, with a total mean (± SD) of 0.054 ± 0.099 MP items/g. Based on this mean and on EFSA recommendation for fish consumption by adults or the general population, human consumers of Dicentrachus labrax, Trachurus trachurus, Scomber colias may intake 842 MP items/year from fish consumption only. Based on the mean of MP in fish muscle and data (EUMOFA, NOAA) of fish consumption per capita in selected European and American countries, the estimated intake of microplastics through fish consumption ranged from 518 to 3078 MP items/year/capita. Considering that fish consumption is only one of the routes of human exposure to microplastics, this study and others in the literature emphasize the need for more research, risk assessment and adoption of measures to minimize human exposure to these particles. Thus, MP pollution and its effects should be further investigated and addressed according to the WHO 'One Health' approach.

Planktivorous pelagic fish are susceptible to accumulating microplastics (MP), which have the same size range as their prey and accumulate in their feeding and spawning grounds. We analyzed stomach contents of pelagic fish (European sardine, horse mackerel, anchovy, chub mackerel, Atlantic mackerel, and bogue) from Atlanto‐Iberian waters to investigate the relationship between MP ingestion, their diet composition and select a potential bioindicator. We found significant differences between diet of the studied fish species in terms of prey type and size. MP ingestion was significantly related to diet composition. Species with diets that include smaller prey (European sardine, chub mackerel, and bogue) had lower MP concentration in the stomachs than fish depending on larger mesozooplanktonic prey. Horse mackerel had the highest proportion of larger prey (> 1000 μm) and the highest MP abundance in the stomachs, and thus are a suitable bioindicator for MP monitoring in the pelagic Iberian ecosystem.

Wild fish (Cyprinus carpio, Mugil cephalus, Platichthys flesus) from an estuary of the NE Atlantic coast were investigated for plastic contamination (N = 128). From the 1289 particles recovered from fish samples, 883 were plastics. Among these, 84% were fibres and 97% were microplastics. Thirty-six polymers were identified. The number of microplastics (mean ± SD) per individual fish (MP/fish) was 8 ± 6 in C. carpio, 10 ± 9 in M. cephalus and 2 ± 2 in P. flesus. The means of MP/fish per body site were 6 ± 7 in gastrointestinal tract, 0.5 ± 1.1 in gills, 0.3 ± 0.7 in liver and 0.6 ± 1.2 in muscle samples. A few large fibres in liver (≤ 4841 μm) and muscle (≤ 5810 μm) samples were found. The results evidence the existence of high fish contamination by microplastics and reinforce the need of further research on plastic pollution in estuaries.

The accumulation of microplastics (MP) by marine species of ecological and commercial interest represents a major concern, particularly for those present in human diet. This study analysed the accumulation of MP in three species of coastal pelagic fish with high commercial value, European sardine (Sardina pilchardus), European anchovy (Engraulis encrasicolus) and horse mackerel (Trachurus trachurus), collected along the Western coast of the Iberian Peninsula. The gastrointestinal tract (GT), gills and muscle were analysed and a total of 504 particles were observed. MP were found in all target tissues of the studied species. Horse mackerel exhibited significantly higher concentrations of microplastics in GT compared to other tissues. On the other hand, anchovies and sardines had significantly lower microplastic concentrations in their muscle tissue. The accumulation of microplastics in the gills showed a significant difference between species, with anchovy having significantly higher concentrations compared to horse mackerel. Horse mackerel had the highest percentage of individuals with microplastics in their GT (92 %), followed by sardine (75 %) and anchovy (50 %). Horse mackerel was also the species that registered the highest percentage of individuals with particles in the muscle (63 %), followed by anchovy (40 %) and finally sardine (39 %). MP in the gills of European sardines and anchovies were similar to those found in water samples. The majority of MP found measured <0.5 mm and were blue fibers. Furthermore, the presence of MP in the GT showed a weak and moderated significant negative correlation with the Fulton Condition Index in horse mackerel and European sardine. Our study confirms the ubiquitous extent of MP contamination in the ocean and provides baseline evidence of MP tissue distribution in three small pelagic fish species with distinct feeding behaviour, while correlating this with the presence of MP in water. Importantly, the results of this study contribute to improve the understanding of biological partitioning of MP in open sea fish species with high commercial relevance, and the potential deleterious effects of our increasingly MP contaminated world.