Feeding strategy of pelagic fishes caught in aggregated schools and vulnerability to ingesting anthropogenic items in the western equatorial Atlantic Ocean.
The present study aims to assess the diet composition of five commercial pelagic fishes caught in aggregated schools in the western Atlantic, quantify plastic and anthropogenic items in stomach contents, and analyze the possible relationship between their diet composition and the occurrence of anthropogenic items. We collected 807 stomachs from tunas (Thunnus albacares, Thunnus obesus, and Katsuwonus pelamis) and tuna-like species (Coryphaena hippurus and Elagatis bipinnulata) targeted by fisheries around data buoys in the western tropical Atlantic between 2011 and 2017. We quantified items of an anthropogenic origin by calculating frequency of occurrence. Feeding strategy was determined using a 3D scatterplot. Correspondence analysis (CA) was performed to determine the relationship between food items and the occurrence of anthropogenic materials (synthetic or organic). Fishing ropes and chum were the main items of an anthropogenic origin. Rainbow runner (E. bipinnulata) stomachs had the highest percentage of such items, whereas none were found in the bigeye tuna. The most affected species by anthropogenic items feed on epipelagic prey items, such as flying fishes. Organisms that aggregate around floating objects on the ocean surface and have a generalist diet are more likely to ingest synthetic items either accidently or actively. The present findings underscore the importance of environmental education programs to mitigate the impact of marine debris on organisms and ensure the health of individuals as well as the balance of the food web to which these species belong.