Our oceans are in jeopardy from plastic pollution

by Thomas Jensen
Plastic bottle

A conference challenges marine litter

This article was featured in Eurofish Magazine 3 2022.

Marine litter has become one of the world’s most serious environmental dangers, threatening everything from fish to whales. And marine litter threatens human life as well.

Debris in the oceans—as well as in lakes and rivers—can be ingested by aquatic organisms—many of which may be commercially important species. The debris breaks down into micro- and nanoplastics, spoils recreational and cultural experiences, and strangles and kills aquatic life. For example, according to UNESCO, plastic in the ocean kills more than a million seabirds every year, as well as more than 100,000 marine mammals, including seals, sea lions, and manatees. Sea turtles are also affected. Animals often mistake plastic for food and end up starving to death with stomachs full of plastic.

To combat this problem, the world must focus on the prevention, monitoring, and reduction of marine litter, as well as gathering and sharing knowledge. But most important, perhaps, is that the increasing awareness and changing attitudes of all stakeholders must eventually lead to a serious reconsideration of the production of plastic and who is responsible for its entire life cycle.

The Lighthouse Lofoten conference

The international conference Lighthouse Lofoten was held in Svolvær, Lofoten, 5–6 April, to increase awareness and knowledge of the problem, across the world as well as in the Nordic countries. Hosted by the Norwegian Centre against Marine Litter, the conference aimed to be a guiding light to those who want to prevent sea-based marine litter and to create a solution-focused community working towards a plastic-free ocean.

Marine litter is any manufactured or processed solid material discarded, disposed of, or abandoned in the marine and coastal environment, and most of it is plastic—as much as 80%, according to various estimates. It turns up on beaches, on the seabed, in sediments, in the water column, and floating on the sea surface. It includes bottles, bags, food packaging, lids, straws, cigarette filters, agricultural plastics, industrial pellets, cosmetic microbeads, and especially fishing and aquaculture gear, which is the most prevalent form of marine litter.

Millions and millions of tonnes annually

According to some estimates, 8 to 14 million tonnes of plastic are thrown into our oceans every year. Fifty-one billion pieces of plastic are floating in our oceans—500 times the number of stars in our galaxy. By 2050, there may be more pieces of plastic in the sea than fish. Estimating the amount of marine litter, however, is mostly guesswork based on findings from existing databases, stakeholder consultations, beach-litter assessments, and the experience of such organisations as OSPAR, Marine LitterWatch, and HELCOM.

The amount observed floating in the open ocean represents only a fraction of the total. More than two-thirds of plastic litter ends up on the seabed. Half of the remainder washes up on beaches, and the other half is floating on or under the surface, so counting only floating plastic debris seriously underestimates the amount of plastic in the oceans.

The persistence of plastic

Plastic pollution in the ocean is not going away by itself. Plastics of all kinds degrade primarily through solar UV-radiation-induced photo-oxidation reactions, and as plastic sinks out of the reach of the sun, degradation slows considerably. Crucially though, even as larger plastic items degrade, they break down into micro- and nanoplastics that find their way into our food chain, drinking water, and even the air. It’s impossible to say how long different types of plastic persist in the ocean, but the US National Oceanic and Atmospheric Administration estimates that it takes 450 years for plastic to decompose in the ocean.

Fisheries and aquaculture must bear the greatest responsibility for the tonnes of plastic in the ocean. Recent studies suggest that fishing and aquacultural gear can make up 46% to 70% of the macro plastic in the ocean gyres by weight. The Nordic region has more plastic from fisheries and aquaculture than anywhere else in the world.

Ghost gear—fishing for 450 years

Ghost gear is the common name for lost or discarded fishing gear. Because it is purposely designed to capture aquatic life, ghost gear is the most harmful form of marine debris because it “continues to fish”. According to one source, more than 640,000 tonnes of nets, lines, pots, and traps used in commercial fishing are dumped and discarded in the sea every year. In addition to the harm it does to aquatic life, it can also damage fishing vessels and equipment such as propellers. Plastic can block water intake systems, and it can end up in other fishers’ gear.

In his conference presentation, Joel Baziuk, associate director of the Global Ghost Gear Initiative (GGGI), listed some causes of ghost gear: intentional discard, which is often linked with illegal, unreported, and unregulated fishing; adverse weather conditions or strong currents; marine traffic unintentionally running over deployed gear; spatial pressures leading to gear conflict; tracking system malfunction; snagging on submerged features; improper gear design; neglected upkeep; and improper fishing methods. According to Baziuk, between 5% and 30% of global harvestable fish stocks (depending on the fishery and geography) are killed by ghost gear annually, which is a major threat to global food security and the livelihoods of fishers and coastal communities.

Aquaculture is a culprit too

Although aquaculture currently supplies more than half of the world’s seafood, the scale of plastic pollution from aquaculture facilities does not yet equal that from other sectors. Identifying litter caused by aquaculture is difficult because it is often misidentified and under-quantified in beach-litter analyses owing to difficulties in identifying its source and a lack of detailed categorisation in official monitoring systems.

Traditionally, marine litter from aquaculture and capture fisheries has been considered together, but because the causes are different, it is better to consider the two sources separately. Joel Baziuk explained that pathways for litter from aquaculture include: loss through routine farming operations; extreme weather; deliberate discharge; inadequate recycling; farm decommissioning; lack of awareness and training; and site mismanagement including inadequate waste management, poor siting, improper installation, and deficient maintenance.


All shapes and sizes

Joel Baziuk noted three kinds of debris. Large debris includes sections of aquaculture equipment, such as cage collars, rafts, boats, tanks, piping, buoys, nets, and ropes. Smaller litter includes feed sacks, discarded gloves and clothing, food and drink containers, plastic bags, feeding trays, containers, and fish boxes. Finally, there is miscellaneous material originating from wear and tear on equipment.

There are few figures on the amount of plastic contributed by aquaculture. The only detailed calculation of plastic use and decommissioning rates comes from Norway. A consultation between manufacturers and waste management companies in 2011 estimated that approximately 13,300 tonnes of plastic waste were generated by Norwegian aquaculture, of which 21% was recycled, mainly the nets. MOWI, one of Europe’s largest salmon farmers, recycled 303 tonnes of nets in 2018.

Another source of plastic pollution, which is most often missed in the recording, is cuttings from nets. Fishers trim and repair their nets both on board and in port, and the cuttings often end up in the ocean. According to Ryan d’Arcy Metcalfe, national coordinator and international liaison for KIMO Denmark, many people are working on fishery-related waste, but very few concentrate on net cuttings. He said that it is necessary to change attitudes of both individual crew members and port managers. But of special importance is the need for harbours to include net cuttings in their waste management systems, which most harbours neglect to do now.

Circular economy—The Big Idea

Frode Syversen, managing director of Mepex, is convinced that a circular economy is the most promising strategy to prevent marine littering, globally and in Norway. He says that, to avoid marine littering, we must organise and finance new value chains for plastic. We must shift from a linear economy, which is based on the principle of “take–make–dispose”, to a circular economy, which embraces closed loops that value all resources used. We must abandon our disposable culture. Circular economy keeps products, packaging, and thereby, resources in circulation for as long as possible.

First, a circular economy designs out economic activities that negatively affect our planet, including the release of greenhouse gases, all types of pollution, and traffic congestion. Second, it designs products for durability, reuse, remanufacturing, and recycling to keep materials circulating for as long as possible. Third, a circular economy avoids the use of fossil fuels and non-renewable energy. Products are designed and handled to regenerate ecosystems instead of destroying them.

Frode Syversen feels something is missing from the national Norwegian strategy. “In the past 30 years, we have developed policies for waste reduction, reuse, and material recycling. But we have not been able to break the connection between consumption and the generation of waste. We still have a long way to go to reach the targets set by the Zero Pollution Action Plan that aims to reduce plastic litter 50% and microplastics 30% by 2030”.

According to Syversen, the potential for circularity is decided mostly in the design phase. It entails choosing construction materials that lend themselves to reuse, designing for maximum future functionality, and anticipating what can be repaired, used as spare parts, and recycled.

To eliminate littering by fisheries and aquaculture facilities, he advocates product regulation and extended producer responsibility (EPR) that will assign the obligation for the life cycle of their products to the producers. Port reception facilities should focus on take-back systems and collection facilities that separate materials. He advises that strong economic incentives are necessary. Product design should prevent littering and microplastic emission, which will require new kinds of cooperation in the value chain.

Behavioural ­interventions for ­reducing marine litter

Sohvi Nuojua, who teaches psychology at the University of Oulu, Finland, and is a researcher in Environmental Psychology at the University of Plymouth, reviewed behavioural interventions aimed at reducing marine litter and plastic pollution. Fishers are certainly aware of marine litter. After all, they are the ones losing costly gear. Many are aware of the serious consequences to the environment, but also of the public’s possibly negative perception of fishing based on fishers’ role in contributing to plastic pollution. Awareness-raising and spreading information only work if the context allows. Studies show that desirable values and practices are hampered by the lack of infrastructure, institutional support, and appropriate practical arrangements in harbours.

Bjørn Vidar Vangelsten of the Nordland Marine Institute agreed with Sohvi Nuojua that, as one fisher explained it, “Ten years ago, [dumping refuse] was common, because it just disappeared. It was ‘out of sight, out of mind’.” Now, even as a younger generation of fishers becomes more aware, they say that sorting waste on board and in the harbour is problematic. Limited space on board is one issue; however, the main reason that fishers forego sorting is the inadequate facilities in harbours and at fish landings to receive sorted waste. For example, many harbours do not offer services for collecting discharged fishing gear. Fishers claim that the cost of adequately disposing of marine litter, in addition to the time and effort it takes to collect it, disincentivises them from collecting or retrieving it (as in Fishing for Litter schemes).

Knowledge is power to combat litter

Knowledge is the key to understanding the many ways that plastics end up in the ocean, and what we can do to prevent it. Naturally, knowledge must pass through all participants in the seafood value chains (fisheries and aquaculture), including equipment designers and manufacturers; fishery, aquaculture, environmental protection, and waste management agencies; harbour and port operators; environmental researchers; nongovernmental organisations; producer associations; sector managers and regulators; and ecolabel and certification programmes.

Databases that store and share information about all aspects of marine litter are essential to the implementation of effective and targeted measures against litter. Many of the organisations represented at the conference have developed complex and growing databases that cover different aspects of marine litter. They include Nordic Coastal Cleanup, Norwegian Centre against Marine Litter (Rent Hav), Global Ghost Gear Initiative (GGGI), KIMO Denmark, and the CleanAtlantic Project.

Beyond just picking up trash

More focused scientific research is needed, but even without it, it is clear that marine litter is a problem that can’t be ignored. Plastic production and consumption will continue to increase. Achieving even already-established objectives for reducing marine litter remains a huge challenge, which is unlikely to be met without a fundamental reconsideration of the ways we consume plastic. Action is needed by all stakeholders to end the waves of plastics and toxic chemicals that are surging into the marine environment.

—William Anthony

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