Another Life: From whales to prawns: the plastic peril in the sea
Plastic litter that has ended up in the ocean is taking a special toll on marine life
Nephrops prawn: more than 80 per cent of them collected in the Clyde firth in Scotland and surrounding sea lochs had eaten plastic, including monofilament line and fragments of plastic bags. Illustration: Michael Viney Nephrops prawn: more than 80 per cent of them collected in the Clyde firth in Scotland and surrounding sea lochs had eaten plastic, including monofilament line and fragments of plastic bags. Illustration: Michael Viney
It’s a good 15 years since I first took note of nurdles – a nonsense name for an insidious substance. Feather-light, translucent beads of polypropylene, no bigger than a lentil, they’re shipped around the world in vast billions as the raw material of plastic manufacture. Far too many end up in the ocean. Rummage among the seaweed at the very highest tideline and the chances are there’ll be some in the sand. That’s how I first came across them, when looking for Caribbean sea beans.
No one knows for sure where the goonish name came from (a nurdle, supposedly, is also the amount of toothpaste you squeeze on to the brush). And no one knows for sure how most of them get into the sea. Just one lost shipping consignment would hold too many to count. An official clean-up of San Francisco Bay blamed spillages from railcars unloading at plastic factories, the pellets washing into storm drains and out into the waves.
Nurdles can look very like zooplankton or fish eggs, the food of much marine life and many seabirds. In Scotland, their accumulation at the shores of the Firth of Clyde and the Firth of Forth has prompted recent volunteer “hunts” for them. At one Cornwall peninsula, a section of beach of some 370sq m yielded more than 400,000.
Along with all discarded plastic, nurdles fragment into smaller and smaller particles. In the “microplastics” of current marine pathology they join granules used for air blasting and abrasive powders in cosmetic and cleaning products, all finer than sand. But plastic particles are now eaten by almost everything, invading the tissues of even barnacles, marine worms and mussels.
My interest was nudged again when it comes to whales – more specifically, True’s beaked whale, Mesoplodon mirus, a deep-diving species first named from one washed up in North Carolina a century ago. By remarkable chance, I found only the seventh and eighth corpses on record in my beachcombing patrols of the 1980s. The first, arriving on the strand below, was eventually salvaged for its skeleton by the Ulster Museum.
Remarkably for such rare events, three more, including mother and calf, were washed ashore on the coasts of Donegal and Connemara in 2013 bringing the Irish total to 13. In changed times, they were promptly autopsied for the Irish Whale and Dolphin Group (IWDG). Microplastics were found throughout the digestive tract of one adult, and some larger plastic pieces in both. (In 2013, a sperm whale was washed up in southern Spain with 30sq m of greenhouse plastic in its stomach.)
The researchers for IWDG were Gema Hernandez-Milian from University College Cork and Amy Lusher of the Galway-Mayo Institute of Technology. Dr Lusher had earlier found microplastics in about one-third of 10 kinds of fish from the English Channel (reported in Marine Pollution Bulletin).
In Scotland, more than 80 per cent of Nephrops prawns collected in the Clyde firth and surrounding sea lochs had eaten plastic, including monofilament line and fragments of plastic bags (as reported at the bulletin).These prawns are the most valuable catch of both Scottish and Irish sea fisheries.
More hydro carbon-based plastic was produced in the first decade of this century than the whole of the previous one, and another 33 billion tonnes seems probable by 2050. Its ubiquity in both the substance and marine life of the planet is now reckoned part of the new geological era of Earth, known as the Anthropocene, or “man-made”.
And what of the plastic litter at Irish tidelines? Coastwatch Europe, the beachcombing network founded first in Ireland by Karin Dubsky of Trinity College Dublin, now has a growing army of volunteers walking the shores of eight countries.
In beach litter mapped from last autumn’s all-Ireland patrols were 14,415 plastic bottles – a total “in keeping with previous years“ – along with plastic rope, string and bottle caps on about two-thirds of shores (coastwatch.org). Partly thanks to Dr Dubsky, a charge for plastic shopping bags has at least helped to reduce their role in tideline debris.
Plastic bags, along with burst balloons, have taken a special toll on marine life, notably of turtles that mistake their underwater shapes for edible jellyfish and die of blocked intestines. Ashley Shak, an American with Caribbean experience of turtle damage and now an intern with Coastwatch, specialises in study of balloon waste. She has warned that even “biodegradable” latex balloons “become sticky and clog throats of animals and take 6 to 12 months to decompose.” Their loss of elasticity, beginning after weeks in dry sunlight, takes far longer in the sea.
Mass releases of helium-filled balloons have already been banned by some local authorities in the United Kingdom, United States and Australia, but surveys by Britain’s Marine Conservation Society find that balloons and their pieces have tripled in the past 10 years. Such releases appear with troubling regularity on RTÉ television news, and more may be suggested for celebrating something or other in this anniversary year. Second thoughts could be a good idea.
Michael Viney’s Reflections on Another Life, a selection of columns from the past four decades, is available from irishtimes.com/ irishtimesbooks