A turtle eating a plastic bag, a seahorse wrapped around a discarded cotton swab, a rotting seabird carcass with a belly full of bottle tops.

These bleak images powerfully illustrate how our oceans are becoming a "plastic smog", a Kiwi researcher says.

But the way we're trying to save our species from the scourge might not be focused where it should be.

In a new study, Auckland University of Technology marine biologist Steph Borrelle and Australian colleagues have highlighted an apparent "disconnect" between research examining plastic pollution and wildlife conservation itself.

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They argue that we need to shift from simply documenting these tragic cases of plastic ingestion in lone animals to investigating what the long-term effects on wildlife may be.

Borrelle, who has led campaigns to ditch single-use plastic bags, said the pollution of our oceans was an "urgent problem" for the multitude of life that lived within it.

"As a seabird conservation ecologist, I think it's really important to talk about how we will protect seabirds, and all the wildlife that is being affected by our plastic waste - because it isn't going to go away any time soon."

And it couldn't be more important to New Zealand, which could boast more seabird species than anywhere else in the world.

Many of these were endemic native, like the Buller's shearwater, which only breeds on the Poor Knight's islands in the Hauraki Gulf.

"It's a terrible statistic that nearly 90 per cent of our seabirds are threatened with extinction," she said.

"We've spent a lot of effort and money on getting rid of predators, like rats and stoats that eat birds and their eggs, from our islands.

"That's inspiring – and it's working to protect seabirds and other native species, unfortunately we have a new problem, seabirds are eating our plastic pollution."

As surface feeders, seabird species tended to eat what they saw - and that included floating plastic they mistook for food.

In the study, just published in the journal Science of the Total Environment, Borrelle and her co-authors pointed out how plastic ingestion research can and should be bridged with front-line conservation work with affected wildlife.

"More than 700 species of marine life are known to ingest plastic, and we are starting to see lots of great research coming out about how plastic ingestion and the toxic chemicals that can leach into animals who ingest plastic might be affecting wildlife at the population level," she said.

"What we are not seeing is enough research about what we can do to offset the impacts of plastic pollution on wildlife."

The authors suggest that plastic ingestion research needs to be framed in such a way that it helped conservation managers find ways of reducing the impacts to species we were charged with conserving.

Each year, humans were now dumping more than 8 million metric tonnes of plastic into the marine environment - equivalent to the weight of 24 jumbo jets. Photo / File
Each year, humans were now dumping more than 8 million metric tonnes of plastic into the marine environment - equivalent to the weight of 24 jumbo jets. Photo / File

"By itself, documenting plastic ingestion is an interesting exercise but as Plotinus said nearly 2000 years ago, knowledge, if it does not determine action, is dead to us."

Still, she said, the issue remained a chicken-and-egg situation - we needed more data to really know what the impacts were, but by the time we knew enough, it could be too late.

"It's a risky situation," she said.

"Plastic has been showing up in wildlife since the 1950s but we've only recently been asking questions about the potential harm it may cause, so there is limited long-term population level data that is needed to answer these types of questions.

"In terms of conservation of wildlife that is affected by plastic pollution, the most pressing issue is shifting the approach of the research community towards thinking more broadly about how plastic pollution is affecting a species."

As it stood, humans were each year dumping more than eight million metric tonnes of plastic into the marine environment - that was equivalent to the weight of 24 jumbo jets, or Eden Park stadium stacked with plastic more than a kilometre high.

"There is already a crisis caused by humans influence on the land, its resources and its climate - plastic pollution may be the last nail in the coffin for many species." Photo / 123RF

"Hundreds of species of marine life are affected by this – from eating or entanglement to death, and plastic can leach toxic chemicals into animals that eat it," she said.

"There is already a crisis caused by humans' influence on the land, its resources and its climate - plastic pollution may be the last nail in the coffin for many species."

Back to those grim pictures of sealife, Borrelle hoped they'd at least offer a stark reminder of how we'd gone too far and neglected our duty of care.

"Hopefully seeing these kinds of pictures helps people see that their behaviour can both positively and negatively impact wildlife - that they will stimulate positive behavioural changes where people choose a lower-plastic life," she said.

"As we learn more about the harmful contaminants seen in plastic ingestion in animals, such as in the kai moana that we consume, people will see the far-reaching population scale impacts of plastic pollution and how it affects us all."

The Buller's shearwater, which only breeds on the Poor Knight's islands in the Hauraki Gulf, is among endemic species threatened by plastic pollution. Photo / Graeme Taylor
The Buller's shearwater, which only breeds on the Poor Knight's islands in the Hauraki Gulf, is among endemic species threatened by plastic pollution. Photo / Graeme Taylor

Microbead ban kicks in this week

Meanwhile, new rules that ban many products containing plastic microbeads kick in this week.

"The microbeads are found in some common household products like face and body scrubs or exfoliators, 'wash-off' products like glitter bubble bath, heavy-duty hand soaps and in some toothpastes," said Dr Fiona Thomson-Carter, general manager of the Environmental Protection Authority's Hazardous Substances Group.

"Plastic microbeads are not biodegradable, and at less than five millimetres in size, many end their life in the sea when they are washed down drains."

Once in the sea, they could absorb and leach toxins over time, and can potentially harm New Zealand's marine life.

Once eaten by marine life, they can potentially become a part of the human food chain.

"Under the new rules many, but not all, products containing microbeads are banned," Thomson-Carter said.

"We have some guidance for the public, manufacturers and interested parties on our website, which we encourage everyone to read.

"This will help people understand what to do if they own or manufacture products that contain plastic microbeads which are covered by the ban."