How Plastic Ends Up in the Ocean

Marine debris is one of the most pervasive threats to marine life and ecosystems globally. It has been considered a major international issue since the 1970s. Litter in the oceans can harm or kill wildlife, pollute beaches, and become hazardous to ships and humans in the ocean (Jones, 1995).

It is estimated that 6.4 million tons of debris enters the oceans per year, and that abandoned, lost, or discarded fishing gear makes up 10% of that figure (Gilman, 2015). The proportion of derelict fishing gear to total marine debris varies by location, primarily based on the local fishing pressure. Locations on shore or close to shore are more prone to land-based debris whereas in offshore areas the greatest driver of plastic pollution is in the form of fishing gear (Macfayden et al., 2009).

Marine debris is an international problem and can come from land or sea-based sources.  Land based sources include the litter we are familiar with on a daily basis, like packaging, food containers, and single-use plastic items, among others. Alternatively, sea based plastics come from either purposeful dumping or accidental loss at sea while on boats including fishing and shipping vessels as well as cruise lines. On average, derelict fishing gear accounts for approximately 10% of marine litter by volume (Macfayden et al., 2009). That means the remaining 90% is either terrestrial in origin or is a result of at-sea garbage dumping.

The proportion of marine debris originating from land sources versus sea sources can vary widely based on the location of interest. Near shore and urban areas have a higher proportion of land-based litter, often around 75% to 80% (Macfayden et al., 2009). This has resulted in a lot of confusion about the extent of fishing debris in the ocean. 

In 2018, a scientific article entitled “Evidence that the Great Pacific Garbage Patch is Rapidly Accumulating Plastic” was published in Nature.

This article was very clear that their results were specific to the garbage patch in the Pacific Ocean, a remote location that is frequented not by people utilizing coastline or for regular travel, but predominantly by fishing vessels and shipping vessels. The researchers in this study found that 46% of the plastic debris in their sample area was fishing debris. This is not surprising for an area so removed from densely inhabited areas. However, the narrative was twisted by some sources that decided to use this statistic and apply it to the oceans globally.

Headlines such as:

“WOW! Survey Finds 46% of Ocean Plastic is Discarded Fishing Nets”

“Ghost Fishing Nets Make Up 46% of Ocean Plastic”

“Dumped Fishing Gear is Biggest Plastic Polluter in Ocean, Finds Report”

These statements are outright lies, and blatantly incorrect.

The article from Nature is easily searchable and readable, and the results provided do not reflect the aforementioned statements. The researchers involved do not extrapolate their results to include the entire ocean, because the garbage patch is not representative of the whole ocean. It is not accurate to conflate pollution sources entering coastal environments and making their way to more remote regions by currents, and pollution entering those remote regions directly. 

As an example, in studies involving beach cleanup surveys in the US, fishing gear made up only 6.1% of litter items.  In coastlines in Japan, only about 11% of plastic debris was fishing gear. Alternately, areas more removed from human influence, such as the Pacific garbage patch, display higher rates of derelict fishing gear can see variation between 50% to 90% of total marine debris.  This will depend entirely on how remote these areas are from human influence and the currents that may or may not drive terrestrial pollution to these regions (Macfayden et al., 2009).

This is not to say that ALDFG (abandoned, lost, or discarded fishing gear) is not an important issue, or is not highly destructive. It absolutely is. It’s just wrong to say it makes up the majority of global plastic pollution. Ghostfishing, or the incidental death of marine organisms due to ALDFG or other unmonitored gear, is a major problem for many species.

It’s important that we address this misinformation because when we blame fishing vessels in the middle of the ocean for the large part of worldwide plastic pollution, we reduce some of the burden on ourselves. I have seen the argument that “fishing gear is the majority of plastic pollution” used to assert that living plastic free or zero waste is pointless. A narrative is pushed that says our collective lifestyle choices can’t change anything because the impact pales in comparison to that of the fishing industry. But that is not the case. The fact is, reducing your footprint is not pointless. Fishing gear is actually not the better part of the ocean plastic pollution problem, regular trash is. 

How plastic gets into the ocean:

As specified in the UN’s investigation into fishing debris, about 10% of the plastic pollution in the ocean is fishing gear. That leaves about 90% on average coming from alternate sources.

Besides fishing gear, there are other sea-based sources of plastic pollution. These can come from fishing vessels as regular trash items, and from shipping vessels and cruise ships. Each of these industries has been historically guilty of introducing trash into the oceans, either intentionally through illegal dumping or accidentally, such as loss overboard with strong winds or waves. The dirty secret about cruise lines – dumping trash overboard is common, and it is only recently that these companies have even tried to cover it up. When I was at NOAA, I heard plenty of stories about how cruise lines used to blatantly toss trash bags overboard, often times with their own logos on the trash bags. Once the alarm was raised, these branded trash bags disappeared, replaced by inconspicuous versions.

From land, there are many ways trash can enter the waterways and out to sea.

One way is through the pipes. Whether it be the laundry drain, sweeping away microfibers and microplastics from clothing; the sink, where certain face washes introduce microplastic beads used for exfoliating; or down the toilet with the flushing of inappropriate items like wet wipes, contact lenses, and sanitary products.

The obvious method is through littering. Some people still intentionally litter, and some occurs unintentionally. We’ve all been guilty of dropping something like a napkin that gets carried away by the wind before we can catch up to it – unfortunately, sometimes the accidental loss is a plastic item. Intentional littering of cigarette butts is still commonplace, and beaches are areas where things like water bottles, drink cans, and food packaging are regularly left behind.

Let’s say you don’t eat fish, don’t go on cruises, and only utilize the local economy, no need for shipping. You only wear natural fibers, have gotten rid of your microbead face wash, and never flush anything you shouldn’t, and you definitely don’t litter. There’s no way you could be contributing to ocean plastic pollution, right? Not exactly.

This is the reason I decided to go zero waste. To me, it’s about reducing what we send to landfills. In a perfect situation, all the trash we produce would go to and stay in landfills. However, trash items can fall of the truck on the way to the landfill, and end up as pollution. Once in the landfill, it can be swept away with rain, or blown away by wind. Garbage exporting is huge in western countries like the United States, where I’m located. A large amount of our landfill waste is exported overseas to places where pollution restrictions are less stringent. The exported garbage can be dumped directly into waterways. According to the WWF, 87% of mismanaged waste is leaked into nature and contributes to plastic pollution. So, to be clear, your trash that you responsibly disposed of in your bin can end up in a distant water mass with relative ease.

Most importantly:

If you see a claim on the internet that appears to be especially grandiose, make sure you find the original source. Many, many people believed the second-source articles that claimed that almost half of plastic pollution in the ocean is fishing gear. Always find the primary source, because scientific findings can be easily misconstrued or misinterpreted. 

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