Plastic ingestion in seabirds of the western Indian Ocean

We investigated seabird plastic ingestion in the western Indian Ocean by analyzing the stomach contents of 222 individuals belonging to nine seabird species (including two endangered species endemics to Reunion Island). The most affected species were tropical shearwaters (79%) and Barau's petrels (59%). The average number of plastic particles per contaminated bird was higher in Barau's petrels (6.10 ± 1.29) than in tropical shearwaters (3.84 ± 0.59). All other studied species also showed plastic presence in their stomach contents. The mass of plastic particles was significantly higher both in juvenile's Barau's petrels and tropical shearwaters than in adults. These results demonstrate the foraging areas of seabirds of the western Indian Ocean have a high level of plastic pollution. In Reunion Island, hundreds of tropical shearwaters and Barau's petrels are attracted by urban lights and die each year. We suggest taking advantage of this situation by using these species as long-term indicators of plastic marine pollution in the region. •First study to investigate plastic pollution in seabirds in the Indian Ocean•The level of plastic ingestion rate ranged from 15% to 79% depending on the species.•One of the two most impacted species is the endemic and endangered Barau's petrel.•Number of plastic particles was higher in Fledgling Barau's petrels than adults.•Barau's petrels and tropical shearwaters as bioindicators of plastic ingestion