Clean, lean, protein. It gets our brain working and our fat burning. Readily available, fresh or frozen, live or dead, it’s undeniable that the demand for bony fish is higher than ever.

But what do you least expect to be speckled within your sashimi, or weekly fish and chips? Perhaps an amassment of petrochemicals? You know, the clear stuff that holds your grocery shopping. The unsavoury truth is that we are likely consuming plastic every time we eat fish.

Because plastic has many different chemical formations, it takes a varying amount of time to break down in the ocean. And by break down, I mean out of human sight. After an average use time of 12 minutes, a plastic bag may disappear after 100 years, cutlery could take up to 1000 years, and bottles may never decompose.

Plastic enters rivers and water catchments through stormwater drains, littering and wind, to eventually make its way out into the big blue. Some debris may wash up on your favourite surf beach, while other debris shows resilience, drifting long distances before joining the polar bears in the Arctic or humpback whales in the Antarctic. Or it may collect into one of the world’s five largest ocean gyres.

Ocean gyres are formed by the rotation of the earth, shape of dry land, and surface winds, and they provide a circulating abyss for plastic. They assist in driving the ‘great ocean conveyor belt’, which circulates water around the entire planet. Water contained inside the huge whirlpools is stationary, proving a virtual rubbish dump in the middle of the ocean.

The ‘great Pacific garbage patch’ has made the North Pacific gyre the most famous of the five. It is the largest accumulation of ocean plastic in the world. Spread over 1.6 million kilometres, it is home to more than 79,000 tonnes of ocean garbage. Upon observation, you may see the odd coffee cup, straw, bottle, all the evils. But it is what you cannot see that poses the most threat.

While some natural materials such as wood, glass or metal can quickly break back down in to the organic components that fuel life on earth, plastic cannot. Instead, the action of water will simply break it into smaller pieces of plastic – cue microplastics. Defined by Dr Google as ‘extremely small pieces of plastic debris in the environment resulting from the disposal and breakdown of consumer products and industrial waste’, their size mimics that of plankton and algae – the foundations that support the entire ocean food chain. That, and the diet of seafood-loving homo sapiens.

In extreme accumulation, it creates a stagnant soup of toxic microplastics, limiting nutrients for the growth of plankton and algae. Travelling visitors such as whales, turtles and seabirds rely on the scarce supply of plankton and fish to survive. Instead, they are mistaking harmful microplastic for nutritious plankton and consuming huge amounts. This gives the false feeling of a full tummy without nutritional benefits, causing malnutrition. Not only do the toxic chemicals within the plastic cause liver and stomach issues, they bioaccumulate up the food chain. As fishing crews haul in seafood that has either directly consumed plastic, or consumed prey affected with plastic, those toxic chemicals may be ending up on our plate.

This does not just occur in the ocean garbage patches, those sprinkles of doom travel around the world in currents. Marine animals everywhere have been found with plastic in their stomachs; seabirds, invertebrates, mammals, and fish. Recently, 29 kilos of plastic was found in the stomach of a dead sperm whale in Spain. And by 2050, 99 percent of seabirds will have ingested plastics.

Fish are not the only popular seafood affected by this; fancy some microplastics in your mussels? Bivalves and other shellfish are filter feeders, and literally munch to purify the ocean, ingesting small plastic particles along with their food. They are going above and beyond: a recent UK study based in popular supermarkets found 70 pieces of microplastic in every 100 grams of mussel.

It is as if the ocean is feeding our trash back to us.

The scary thing is, there is still little research into the effect of plastic consumption in humans. Although it is known that plastic acts as a sponge to POPs – Persistent Organic Pollutants. These are industrial chemicals, pesticides and other synthetic pollutants that are present in the ocean and cling to plastic. They are knowingly toxic to humans, causing reproductive, endocrine, immune and neurobehavioural problems, and even increased cancer risk.

At some stage fish may be friends not food.

So if you want to eat less plastic? Ditch the disposables. I’m talking single-use plastics that are literally used once then disposed of. These are what contribute the majority of the rubbish in the ocean. Start by giving up the big four – plastic bottles, straws, coffee cups and bags. Don’t be that guy at the supermarket.

There are durable, guilt-free alternatives readily available in the forms of cloth bags, metal straws, glass/reusable containers and bottles. Be wary of your takeaways. Sushi packets are useful for the entire four minutes it takes to scoff that California roll – and then they are around forever. BYO container, or better yet, pressure suppliers to get up with the times and produce compostable packaging. Make a habit to buy local produce, the majority of processed food are packaged in plastic – ditch those and you and the ocean will be a damn sight healthier.

Veronica Rotman is studying for an MSc in Marine Science at the University of Auckland.

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