Whales’ appetite for plastics yawns wide

A dead pygmy sperm whale after stranding in Florida. Image: By Inwater Research Group, via Wikimedia Commons

Polluting fragments and fibres get everywhere. Whales’ appetite for plastics shows how that includes the living tissue of some of the biggest sea creatures.

LONDON, 6 February, 2019 − There seem to be few limits to whales’ appetite for plastics. Scientists who checked the stomachs and intestines of 50 whales, dolphins and seals found stranded and dead on British coasts have identified plastic particles ingested by every one of them.

So far the researchers make no link between what now seems ubiquitous plastic pollution of the seas and the health of the animals – the numbers in each were tiny – but the find is yet another indicator of the steady degradation of the planet’s biggest natural habitat by just one terrestrial species with a lately-acquired addiction to fossil fuels.

A small fraction of the world’s oil, coal and natural gas output is turned into plastics or organic polymers with versatile and enduring properties, and four-fifths of the particles were identified as synthetic fibres from clothes, fishing nets and toothbrushes: the remainder may have come from food packaging and plastic containers.

“It’s shocking – but not surprising – that every animal had ingested microplastics,” said Sarah Nelms of the University of Exeter and the Plymouth Marine Laboratory, who led the study.

“The number of particles in each animal was relatively low (average of 5.5 particles per animal) suggesting they eventually pass through the digestive system, or are regurgitated. We don’t yet know what effects the microplastics, or the chemicals on and in them, might have on marine mammals.”

“Over the years we have found microplastic in nearly all the species of marine animals we have looked at”

The find was not surprising because in the last few years researchers have repeatedly established that in the century since the first synthesis of artificial polymer materials, colossal quantities have ended up in the oceans in ever-tinier particles: they have been found in the high Arctic, in every litre of sampled seawater, in coral reefs and in polar bears.

The scientists write in the journal Scientific Reports that they found at least one microplastic particle in every animal they examined, in either stomach or intestine.

Altogether, in 10 species – the Atlantic white-sided dolphin, the bottlenose, common, striped, white-beaked and Risso’s dolphins, the grey seal, the harbour seal, the harbour porpoise and the pygmy sperm whale − they found 273 particles, and 261 of these were smaller than 5mm. Most were fibres, ranging in size from 2cms to 0.1mm; 16% were fragments. At least 26 marine mammals are known to use British waters.

Colossal quantities of microplastics get into the sea from a variety of sources. Rain washes away fragments of tyres and paint; debris gets spilled during transportation; microbeads get washed out of fibres and cosmetics; large objects get abraded, crushed and fragmented.

Effects unknown

The smaller the size, the easier it is for the particles to be taken up by small crustaceans called copepods, shellfish, fish, seabirds and the bigger sea creatures and the marine mammals at the top of the food chain.

“Over the years we have found microplastic in nearly all the species of marine animals we have looked at; from tiny zooplankton at the base of the marine food web to fish larvae, turtles and now dolphins, seals and whales,” said Pennie Lindeque, who heads the marine plastics research group at Plymouth Marine Laboratory.

“We don’t yet know the effects of these particles on marine mammals. Their small size means they may easily be expelled, but while microplastics are unlikely to be the main threat to these species, we are still concerned by the impact of the bacteria, viruses and contaminants carried on the plastic.

“This study provides more evidence that we all need to help reduce the amount of plastic waste released to our seas.” − Climate News Network