A study of an internationally important breeding population of a seabird – the Manx shearwater – revealed that almost three-quarters had ingested plastic.
Researchers examined the stomach and gut contents of 34 adult and fledgling birds which had been found dead on Skomer Island in Wales.
The team, from Nottingham Trent University, the University of the West of England, the University of Gloucestershire, Bristol Zoological Society and the Wildlife Trust of South and West Wales, found that nine of the 12 fledglings (75%) had ingested at least one piece of plastic, along with 15 of 22 adult birds (68%).
Together the 34 birds had swallowed more than 70 individual pieces, all smaller than 5mm.
Over half of the world’s Manx shearwaters – approximately 440,000 pairs – breed on the Wildlife Trust of South and West Wales’ neighbouring islands of Skomer and Skokholm.
Shearwater chicks remain in their burrows for up to 70 days after hatching, and are consuming plastics along with fish and squid food brought back to the nest burrow and regurgitated by adults. Adults were found to contain larger plastics than fledglings.
Clear and yellow plastics were most commonly ingested by adults, which the researchers suggest may have been mistaken for prey.
Plastic debris from fishing equipment and river litter is increasingly abundant in the marine environment and seabirds are among the most impacted marine vertebrates.
‘Procellariiformes’ – the order of seabirds which includes shearwaters and their larger cousin the albatross – are mostly surface-feeders and may be particularly susceptible to ingestion of floating plastic.
The researchers argue that the Manx shearwaters may not necessarily have ingested the plastics near to Skomer Island as they forage in the seas of Wales, Ireland, England and North-West Scotland.
They also spend the non-breeding season in the south Atlantic off the coast of Argentina and Uruguay, and so may have ingested plastics on their trans-Atlantic journey. Manx shearwater prey may ingest microplastics, so indirect plastic consumption is also possible, the researchers say.
Posted On: 08/11/2022