Birds of a Feather Eat Plastic Together: High Levels of Plastic Ingestion in Great Shearwater Adults and Juveniles Across Their Annual Migratory Cycle

Abstract

Limited work to date has examined plastic ingestion in highly migratory seabirds like Great Shearwaters (Ardenna gravis) across their entire migratory range. We examined 217 Great Shearwaters obtained from 2008–2019 at multiple locations spanning their yearly migration cycle across the Northwest and South Atlantic to assess accumulation of ingested plastic as well as trends over time and between locations. A total of 2328 plastic fragments were documented in the ventriculus portion of the gastrointestinal tract, with an average of 9 plastic fragments per bird. The mass, count, and frequency of plastic occurrence (FO) varied by location, with higher plastic burdens but lower FO in South Atlantic adults and chicks from the breeding colonies. No fragments of the same size or morphology were found in the primary forage fish prey, the Sand Lance (Ammodytes spp., n = 202) that supports Great Shearwaters in Massachusetts Bay, United States, suggesting the birds directly ingest the bulk of their plastic loads rather than accumulating via trophic transfer. Fourier-transform infrared spectroscopy indicated that low- and high-density polyethylene were the most common polymers ingested, within all years and locations. Individuals from the South Atlantic contained a higher proportion of larger plastic items and fragments compared to analogous life stages in the NW Atlantic, possibly due to increased use of remote, pelagic areas subject to reduced inputs of smaller, more diverse, and potentially less buoyant plastics found adjacent to coastal margins. Different signatures of polymer type, size, and category between similar life stages at different locations suggests rapid turnover of ingested plastics commensurate with migratory stage and location, though more empirical evidence is needed to ground-truth this hypothesis. This work is the first to comprehensively measure the accumulation of ingested plastics by Great Shearwaters over the last decade and across multiple locations spanning their yearly trans-equatorial migration cycle and underscores their utility as sentinels of plastic pollution in Atlantic ecosystems.

Plastic Pollution in Oceans: A Review

“…This case underscores the broader implications of plastic pollution on marine ecosystems, highlighting the urgent need to address plastic pollution comprehensively to safeguard marine life and maintain ecosystem balance. (Robuck et al, 2022) Ingesting plastic has profound and harmful effects on marine life, encompassing a spectrum of physical, chemical, and ecological consequences. Numerous marine creatures, including sea turtles, seabirds, and fish, often mistake plastic items for prey.…”

Aves Marinhas No Brasil: Desafios Para a Conservação

“…Resíduos plásticos confundem as aves, organismos com elevada capacidade olfativa, atraídas pelo dimetilsulfeto, substância produzida pelo fitoplâncton, neste caso aderido ao plástico flutuante (Savoca et al 2016, mas ver Dell'Ariccia et al 2017 pra opinião divergente). Assim, o biofilme em peças plásticas resulta em odores que mimetizam o alimento e são ingeridas equivocadamente (Robuck et al 2022). Com as áreas de alimentação das aves marinhas ao longo da costa brasileira poluídas por plástico (Robuck et al 2022), espera-se um crescente número de registros de interações negativas entre aves e plásticos, como tem sido reportado na bibliografia desde o final da década de 1980(Azevedo & Schieller 1991, com incremento da incidência em anos recentes (Nascimento et al 2022, Daudt et al 2023.…”

Monitoring litter and microplastics in Arctic mammals and birds

“…Importantly, some species that can be sampled in the Arctic migrate long distances, and thus likely reflect plastic ingestion from areas beyond the Arctic. Therefore, species annual ranges influence plastic levels in seabirds, as well as the residence times of plastic particles in the gut of the bird (Robuck et al 2022). As a result, monitoring data on plastic ingestion by seabirds cannot be combined across species into a single metric, and foraging strategies must be considered in the data interpretation.…”