For decades, our oceans have been filled with garbage. The North Pacific Garbage Patch, also known as the Great Pacific Garbage Patch, is home to around 80,000 tonnes of plastic waste – and that’s the estimate continues to rise. Most of the trash in the ocean is carried by rivers, which carry human waste and pollution from land to sea. But the origin of floating debris in sea spots has not been fully elucidated. A recent study published in Scientific reports identified one important source of waste: the fishing industry.
According to an analysis of trash collected by the non-profit Ocean Cleanup Project, 75 to 86 percent of the plastics floating in the Great Pacific Garbage Patch come from marine fisheries and aquaculture. Major industrialized fishing countries, including Japan, China, South Korea, the United States, Taiwan, and Canada, were the main sources of fishery waste. “These findings highlight the contribution of industrial fishing countries to this global problem,” said Laurent LeBreton, lead author of the study and head of the Ocean Cleanup Unit.
The Great Pacific Garbage Patch, a region twice the size of Texas between the west coast of North America and Japan, is one of several eddies in the ocean where waste is accumulating. It is created by eddy currents, or roundabouts, each vortex whips up and shreds plastic into tiny, non-degradable pieces that are hard to scoop up. Plankton nets are used to collect these microplastics, often no more than 5 millimeters in size, LeBreton says. “But now it is impossible to recreate the exact origin of this pollution,” he says.
Since 2018, Ocean Cleanup has been working to remove less common large debris that can sometimes be identified. The team’s approach uses vessels that pull a long U-shaped barrier across the water, channeling large plastics into a catch system. “This gave us a unique opportunity to study large plastic objects that had not been the focus of previous research,” says LeBreton.
During the 2019 mission, the system retrieved more than 6,000 plastic objects larger than 5 centimeters (the threshold for large debris). While a third of the haul was unidentified, the research team sorted through fish boxes, oyster spacers and eel traps. These fishing and aquaculture tools were the second most common type of hard plastic collected, accounting for 26 percent.
As with other sectors of our economy, fishing has taken over from plastics because of their light weight and cheap production costs. This plastic can last for decades.
“We found a fishing buoy from the ’60s and a box from the ’70s, so it must have been built over time,” says LeBreton, noting that the fishing industry has only expanded since the last century. “More than half of the ocean’s surface is now fished, increasing the likelihood that fishing gear will be lost, discarded or abandoned in the ocean.”
The concentration and size of debris in the Great Pacific Garbage Patch is increasing, according to a 2020 study by the organization. “This suggests that the situation is worsening, which is to be expected at this stage with the exponential increase in plastic production over the last two decades,” says LeBreton. “That’s why it’s important to study and identify this contamination so that the effects can be reduced in the future.”
The Ocean Cleanup Project has an ambitious goal of removing 90 percent of marine plastic debris by 2040. Since last year, the team’s upgraded system has plucked more than 100,000 kilograms of floating plastic from the ocean; However, marine biologists have spoken out skepticism about the effectiveness of such cleaning and raised serious problems these techniques can harm wildlife. LeBreton says the nonprofit’s efforts don’t have to be a permanent solution: “We want to end the business eventually.” The best way to reduce plastic waste in these waters is to stop it at the source, he says. Cleanup technologies can help identify the cause and origin of pollution to inform regulation and management. This could include regulating the use of fishing gear or how ships handle their waste, LeBreton says.
“I hope this pollution will be visible [through cleanup efforts] has a significant impact on awareness as well as overall understanding of the issue,” he says. “Documentation of floating plastic pollution must play a role in the development of mitigation strategies. Widespread public awareness can help advance legislation.”
Images and captions from Ocean Cleanup.