The number of identified pelagic and benthic fishes containing plastics and microplastics in their stomachs is about 475.
Plastic pollution has been identified as a major environmental problems for marine biota, beside the CO2 intake and its consequences. Plastic items are now commonly detected from urban coasts to the most distant areas, Arctic and Antarctic.
Synthetic plastics are exceptionally spatially and temporally heterogeneous varying by orders of magnitude within small changes in time or space. But plastic wastes are generally highly resistant to biodegradation and causes varied environmental concerns associated with ingestion, suffocation, accumulation and exerts long-term toxic effects on marine organisms.
A wide variety of fish species, about 475 species identified, are known to ingest plastic items. Particularly around urban coasts, the number of identified fishes containing plastic in their stomachs for any given species has been generally higher compared to distant areas.
In the Azores for example, in the North Atlantic subtropical gyre, a study showed that concentrations of large microplastic (items 1-5 mm) have been to reach 250 000 items/km2 and up to 7 000 000 items/km2 for small microplastic (items < 1 mm).
Within Azorean waters, significant concentrations of plastic items have been recorded floating at the sea surface, on the seafloor or found accumulating on several beaches across the archipelago but also in the gastrointestinal tract of sea turtles.
This co-occurrence of both high biodiversity and high plastic abundance makes the Azores an important case of study to address questions regarding the biological risk of plastics.
Fisheries in the Azores are mostly artisanal and place a high value on fish quality and on sustainable capture methods.
A portuguese study focused on assessing plastic contamination in the stomach of five different fish species of high commercial interest in the Azores, which are blackbelly rosefish, blue jack mackerel, chub mackerel, blackspot seabream, and skipjack tuna. These species are occupying both the pelagic and benthic zones.
Plastic abundance in pelagic fish was significantly higher compared to benthic fishes. Overall, its result confirmed the presence of plastic particles in all five fish species investigated from the Azores archipelago, with most items being smaller than 1 mm.
The general proportion of individuals containing plastics in their stomachs was low compared to other areas in the North Atlantic. But it is highly probable that the total plastic load of the species investigated was underestimated.