Size of plastics ingested by petrels and shearwaters correlates with body size

Lauren Roman (CSIRO Oceans and Atmosphere, Hobart, Tasmania, Australia) and colleagues have published in the Marine Pollution Bulletin on plastic items found in corpses of 20 species of petrels and shearwaters beach-washed or killed by fisheries in Australasia; most were 2-10 mm in dimension.

The paper’s abstract follows:

“Pollution of the world's oceans by marine debris has direct consequences for wildlife, with fragments of plastic <10 mm the most abundant buoyant litter in the ocean.  Seabirds are susceptible to debris ingestion, commonly mistaking floating plastics for food.  Studies have shown that half of petrel species regularly ingest anthropogenic waste.  Despite the regularity of debris ingestion, no studies to date have quantified the dimensions of debris items ingested across petrel species ranging in size.  We excised and measured 1694 rigid anthropogenic debris items from 348 petrel carcasses of 20 species.  We found that although the size of items ingested by petrels scale positively with the size of the bird, 90% of all debris items ingested across species fall within a narrow “danger zone” range of 2–10 mm, overlapping with the most abundant oceanic debris size.  We conclude that this globally profuse size range of marine plastics is an ingestion hazard to petrels.”

A Flesh-footed Shearwater yields its plastic load, photograph by Ian Hutton

Read a popular article on the study here.

Reference:

Roman, L., Paterson, H., Townsend, K.A., Wilcox, C., Hardesty, B.D. & Hindell, M.A. 2019.  Size of marine debris items ingested and retained by petrels.  Marine Pollution Bulletin 142: 569-575.

John Cooper, ACAP Information Officer, 06 June 2019