The Great Pacific Garbage Patch is made up largely of discarded fishing gear rather than household plastic waste, according to two studies published in Scientific Reports. Researchers found that fishing related debris accounts for the majority of large floating plastic in the North Pacific accumulation zone.
The studies estimate that the patch contains around 79,000 metric tonnes of floating plastic spread across approximately 1.6 million square kilometres of ocean. On average, this amounts to about 50 kilograms of plastic per square kilometre, making the pollution far less dense than the commonly perceived image of a floating island of trash.
Researchers found that more than three-quarters of the plastic mass consists of objects larger than five centimetres. Fishing nets alone account for at least 46% of the total mass, while a follow up study estimated that between 75% and 86% of large floating debris by weight originated from fishing activities, including ropes, nets, buoys, floats and traps.
An analysis of identifiable debris linked most of the fishing gear to Japan, China, South Korea, the United States and Taiwan, all major fishing nations in the North Pacific.
The researchers cautioned that the findings apply specifically to the North Pacific Garbage Patch and should not be interpreted to mean that consumer plastic waste is not a major contributor to global marine pollution. They noted that rivers remain the primary pathway through which plastic enters the world’s oceans, while the patch mainly accumulates durable floating debris generated offshore.
The studies also found that although microplastics account for only about 8% of the patch’s total mass, they represent nearly 94% of its estimated 1.8 trillion plastic fragments by number.
A separate 2024 analysis reported that tiny plastic fragments measuring between 0.5 and 5 millimetres are increasing faster than larger debris, with some areas recording concentrations exceeding 10 million pieces per square kilometre.
Researchers said the findings highlight the need for targeted measures such as better tracking of fishing gear, mandatory reporting of lost equipment and improved collection systems at ports to reduce marine plastic pollution. They also called for similar studies in other ocean gyres to determine whether the dominance of fishing gear is unique to the North Pacific or reflects a broader global pattern.