Study: 75% to 86% of plastic debris in GPGP originates from fishing activities

02 / 09 / 2022

By Marwa Nassar - -

A recent study published by the Ocean Cleanup said 75% to 86% of plastic debris in the Great Pacific Garbage Patch (GPGP) originates from fishing activities at sea.

The findings of the study on the composition, origins, and age of plastic debris accumulating in the Great Pacific Garbage Patch (GPGP) add to the understanding of the plastic pollution problem, helping us refine our cleaning strategy and gain insight into the origins of this plastic.

The Ocean Cleanup’s previous research has shown that almost half of the plastic mass in the GPGP is comprised of fishing nets and ropes (fibrous plastics used), with the remainder largely composed of hard plastic objects and small fragments. While the provenance of fishing nets is obvious, the origins of the other plastics in the GPGP have — until now — remained unclear.

Data on plastic debris afloat at sea has typically been based on data collected through small-scale surface trawls, initially developed to collect plankton. Due to their small size, these trawls typically collect small plastic fragments. It is difficult to trace the origins of these small fragments, limiting their usefulness in determining where GPGP plastic comes from.

Larger plastic objects, on the other hand, can sometimes carry clues that can help clarify their age, as well as their source and geographical origin. Such items, however, have only rarely been collected by seagoing researchers. Instead, they are mostly quantified using remote sensing techniques.

Nearly half (49%) of plastic objects which could be dated were produced in the 20^th century, with the oldest identified item being a buoy dating from 1966. This distribution is in line with the previous research showing significant occurrence of decades-old objects in the GPGP and re-emphasizes that the plastic in these garbage patches persists and can cause harm for lengthy periods, continually degrading into microplastics and becoming increasingly difficult to remove. In short, these results underline the urgent need to clean the GPGP; no matter what actions are taken to prevent riverine plastic emissions, the GPGP will persist and its content will continue to beach on remote islands, such as the Hawaiian Archipelago, and fragment into microplastics that will eventually sink to the seabed.

The primary countries/regions of origin identified on the items were Japan (34%), China (32%), the Korean peninsula (10%), and the USA (7%). Perhaps contrary to expectations, however, other countries at the rim of the North Pacific Ocean with high predicted riverine plastic emissions (such as the Philippines, for example) were not well represented in the plastic items collected from the GPGP.

The presence of high quantities of plastic from China, Japan, the Korean peninsula and the USA in the GPGP may not be entirely intuitive; most of these places are not recognized as major sources for riverine plastic emissions into the ocean. However, they do carry out the majority of industrialized fishing activities in the GPGP region.