Table 2.
Comparison between identified origins of hard plastic items > 5 cm collected from the NPGP in 20153 and in 2019 (this study) against modelled contribution of countries for different river7,8,50 and fishing effort48 scenarios.
| Observations | Japan | China | Korea | USA | Taiwan | Russia | Others | ||
|---|---|---|---|---|---|---|---|---|---|
| # plastic items 2015 | 124 | 114 | 64 | 16 | 5 | 1 | 25 | ||
| # plastic items 2019 | 78 | 75 | 23 | 15 | 13 | 1 | 27 | ||
| Total | 202 | 189 | 87 | 31 | 18 | 2 | 52 | ||
| % | 35 | 33 | 15 | 5 | 3 | 0 | 9 |
| R2 | R2* | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Modelled river sources contributing to the NPGP (2013–2019) | |||||||||
| Meijer et al.8 | 3% | 10% | 0% | 1% | 1% | 0% | 86% | 0.01 | 0.00 |
| Borrelle et al.7 | 54% | 4% | 1% | 2% | 0% | 5% | 34% | 0.27 | 0.00 |
| Chen et al.50 | 26% | 2% | 4% | 13% | 12% | 4% | 41% | 0.00 | 0.07 |
| Modelled fishing effort contributing to the NPGP (2013–2019) | |||||||||
| Trawlers | 1% | 73% | 1% | 7% | 1% | 16% | 1% | 0.22 | 0.68 |
| Fixed gear | 2% | 56% | 7% | 12% | 3% | 19% | 1% | 0.16 | 0.61 |
| Drifting longlines | 26% | 10% | 14% | 20% | 25% | 0% | 6% | 0.08 | 0.01 |
| Others/unidentified | 5% | 72% | 5% | 5% | 3% | 7% | 4% | 0.32 | 0.80 |
| All fishing | 5% | 61% | 5% | 9% | 5% | 13% | 2% | 0.26 | 0.71 |
The contributions are weighted with mass inputs in tonnes for the river scenarios and in number of fishing hours for the fishing effort scenario. See Supplementary Table S10 for absolute values. Modelled contribution of countries (Supplementary Fig. S3) is rated by scenarios (Supplementary Fig. S1) and coefficient of determination R2 and R2* are reported for regressions between model and observations, made respectively with and without the contribution of Japan.