Latest research reveals the majority of the plastic mass in the North Pacific Garbage Patch originates from fishing activities.
The subtropical oceanic gyre is a system of ocean currents in the North Pacific Ocean, that is currently covered with tens of thousands of tonnes of floating plastic debris, dispersed over millions of square kilometres. Known as the North Pacific Garbage Patch (NPGP) this is a large mass of floating plastics. Latest research has revealed that a small number of industrialised fishing nations are contributing the majority of floating plastic waste in the North Pacific Garbage Patch, reports a new paper published in Scientific Report.
Previous expeditions have suggested that fishing nets, ropes and larger plastic fragments may form up to three quarters of the objects in the region. A large fraction is composed of fishing nets and ropes while the rest is mostly composed of hard plastic objects and fragments, sometimes carrying evidence on their origin.
In 2019, an oceanographic mission conducted in the area, retrieved over 6000 hard plastic debris items greater than 5 cm. The debris was later sorted, counted, weighed, and analysed for evidence of origin and age.
Over three-quarters of the plastic mass in the North Pacific Garbage Patch originates from fishing activities, and the vast majority comes from five industrialised fishing nations; Japan, China, South Korea, the USA and Taiwan. These results come from a recent analysis of hard plastic debris found in the Patch, but the massive amount of plastic nets and ropes likely comes from the same origins. The study shows that plastic debris from fisheries are ten times more likely to reach the North Pacific Garbage Patch than plastics from river sources, which tend to wash ashore or sink into coastal waters.
The New Zealand-born oceanographer Laurent Lebreton was the lead author of the study, and says the findings highlight the important role fishing industries play in both contributing to and solving the problem of oceanic plastic pollution.
Lebreton and colleagues analysed 573 kilograms of debris (consisting of 6,093 items larger than 5 centimetres) collected from the North Pacific subtropical gyre during an expedition between June and November 2019. The debris was collected from latitudes between 33.0 and 35.1 degrees North and longitudes between 143.0 and 145.6 degrees West. The plastic debris pieces were inspected for evidence of their country of origin, such as language, company name or logo. The authors also modelled how plastic debris may enter the ocean using ocean current data.
Although 33% of the debris were unidentifiable fragments, the second largest category of objects (26%) was fishing equipment such as fish boxes, oyster spacers, and eel traps. Plastic floats and buoys made up 3% of the objects, but accounted for 21% of the total mass. The authors report that, for the 232 plastic objects where the origin could be identified, 33.6% (78) were from Japan, 32.3% (75) were from China, and 9.9% (23) were from South Korea. A further 6.5% (15) of such objects originated from the USA, 5.6% (13) from Taiwan, and 7.3% (11) from Canada. The authors report that, according to their models, plastic debris in the NPGP was more than ten times more likely to originate from fishing activities rather than land-based activities. They note that most of the identified countries contributing to the plastic debris have industrialised fishing.
Lebreton says there is an urgent need for international cooperation and regulations to reduce plastic emissions from fishing industries worldwide. “These findings highlight the need for transparency from the fishing industry and strengthened cooperation between countries to regulate waste management on board fishing vessels and monitor abandoned fishing gear in the oceans”, he says.
Laurent Lebreton MSc is an oceanographer, originally from Raglan, now Wellington. He was the lead oceanographer for a study by the Ocean Cleanup. Other contributors to the study included Sarah-Jeanne Royer, Axel Peytavin, Wouter Jan Strietman, Ingeborg Smeding-Zuurendonk and Matthias Egger.
Read the full report here: Nature Portfolio
Organisation/s: The Modelling House (Raglan, New Zealand), The Ocean Cleanup (Rotterdam, The Netherlands)