We’ve all heard about the plastic problem in our oceans. We’ve seen pictures: great floating garbage islands, and remote beaches covered in straws and bottles. However, the majority of large plastic items are not from consumer waste . Instead abandoned or lost fishing gear “ghost gear” makes up at least 10% of all marine plastic . On an annual basis, around 640,000 tonnes of ghost gear ends up in the sea . Much of this is still capable of catching marine life and is further diminishing overfished marine stocks, making it a ghostly killer .
The benefits of plastic have been significant, not least in the fishing industry where more durable nets are capable of withstanding the force of the seas [3,4]. These nets are also more cost efficient as plastic is cheap to make from oil. Unfortunately, these reasons also make it the worst thing to use in the ocean.
The fishing industry sees plastic gear as expendable, because of its affordability . But we are starting to wake up to the extent of the damage caused by lost gear . Ghost gear can entangle and be ingested by marine wildlife, damage coral reefs, and can degrade to microplastics causing contamination [1,6]. In 2018 over 300 turtles were killed in one net off the coast of Mexico alone . The increase in microplastics in the seas some argue, will do irreversible damage to the ecosystem , and further add to the possible collapse of ocean wellbeing .
Our oceans are important, they regulate weather, absorb carbon dioxide and are home to most of the life on Earth . Three billion people currently rely on fish as their main source of protein . The fishing industry employs around 200 million people globally . However, though demand for fish grows, the volume in the sea does not. Demand and the capacity of the natural environment are not aligned, and we are depleting resources unsustainably.
Sustainable scale relates to the size of the ecosystem and its current and future carrying capacity; scale sets a limit on resource use . Ghost fishing is tipping scale to unsustainable two-fold: by damaging the natural ecosystem through plastic waste, and further depleting marine wildlife levels. In a USA scheme around 10% of ghost crab pots were removed, leading to a 28% increase in catches the following year . The ecosystem can recover, given time, and if we act.
Ecosystems are changed by humanities actions and climatic alterations. Our world is constrained by biophysical limits and the laws of thermodynamics . The total sum of energy resource is finite, but can be transformed from low entropy to high . As we turn oil to plastic, we can never return to the energetic potential of the oil, but can recycle for lesser energetic uses, all the while losing energy through waste processes . Ghost gear is therefore, both a loss of resources which have the potential to be recycled or reused, and marine life.
Environmental economics views problems of scale as merely an issue of the monetary price of the environment not yet being right: once reached, demand falls and equilibrium follows . This view does not consider the huge expansion of the economic system and global population, nor the natural environment we are sacrificing to sustain them . To create sustainable scale, we first need to know what natural resources we have, what we use, and then find a way to resolve the two .
Neoclassical economics explains environmental degradation as a necessary bad, which will, over time improve through development . Traditional materials like hemp or cotton were less durable and became more expensive, but did not cause the same long-term damage to ecosystems if lost . Manufacturers and producers often require financial incentives to change designs or innovate materials . Historically the natural environment was seen as a sink, which could absorb rubbish , so there had been little incentive for innovation in biodegradable plastic nets to occur.
There are regulations and schemes in place which aim to reduce ghost gear. A recent EU directive redirects the cost of gear clean-up from the public sector back to producers . A voluntary scheme Fishing for Litter has led to an increase in marine litter brought back to shore . A UK based Ghost Fishing charity coordinates volunteers to remove spent fishing gear . Investigations in trials of biodegradable fishing gear are underway . But none of these schemes address the fundamental issues of over-consumption and demand through a growing population. We cannot keep fishing and polluting in the same way, something will have to give.
Recent reports of ghost fishing, and consumer awareness of plastic in the seas, may be the tipping point needed for change. Hard questions need to be asked about fair distribution of resources and necessity of consumption. Achieving sustainable scale may not be easy. But, to maintain the health of the oceans, it is vital to tackle the ghostly floating killer.
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