Plastics found in sea-bed sharks

Plastics found in sea-bed sharks - University of Exeter

Lesser spotted dogfish. Credit: Jake Davies

Microplastics have been found in the guts of sharks that live near the seabed off the UK coast.

University of Exeter scientists studied four species of demersal (seabed-dwelling) shark.

Of the 46 sharks examined, 67% contained microplastics and other man-made fibres.

A total of 379 particles were found and – though the impact on the sharks’ health is unknown – the researchers say it highlights the “pervasive nature of plastic pollution”.

“Our study presents the first evidence of microplastics and anthropogenic fibre contaminants in a range of native UK demersal shark species,” said lead author Kristian Parton, of the Centre for Ecology and Conservation at Exeter’s Penryn Campus in Cornwall.

Commenting on the possible sources of the particles, he added: “We were surprised to find not only microplastics (including disposable hygiene items like facemasks as a potential source) but also particles such as regenerated cellulose, which is commonly found in textiles and clothing. When clothes are washed, or items are discarded as litter, tiny fibres are released and these often flow into water sources and out to sea. Once in the sea, microfibres can either float or sink to the bottom, which is where these sharks live. The fibres could then be ingested via the sharks’ food, which is mostly crustaceans, or directly through the sediment on the seabed. In terms of the other types of microplastics we found, many of these may have come from fishing lines or nets.”

The research team, which included scientists from Greenpeace Research Laboratories, examined the stomachs and digestive tracts of four species: small-spotted catshark, starry smooth-hound, spiny dogfish and bull huss.

These species can be found at varying depths from 5-900m, but usually live and feed near the sea floor.

Though the study is based on a modest sample size, the findings suggest larger sharks contained more particles. No differences were found based on sex or species.

The study was conducted in Cornwall, UK, using sharks caught as “bycatch” (by accident) in a demersal hake fishery, fishing in and around the North-East Atlantic and Celtic Sea.