Sampling was conducted at 31 sites in the western Pacific Ocean from 2000 to 2001 with the aim of collecting plastic fragments with a neuston net (mesh size 1.00 mm × 1.64 mm). Small plastic fragments including microplastics (small fragments in the size range of 1.1–41.8 mm) were collected at multiple survey sites. Waters with high densities of small fragments were observed between 20°N and 30°N to the south of Japan and between 20S and 30S to the northeast of New Zealand (maxima of 6.63 × 102 and 2.03 × 102 pieces/ha, respectively). These waters are located to the west of the Ekman convergence zones related to trade winds in the subtropical gyres of the North and South Pacific Oceans. Nearly no small plastics were observed in the tropical circulation of the western Pacific Ocean.
Keiichi Uchida, Ryuichi Hagita, Toshifumi Hayashi, Tadashi Tokai, Fisheries Science, November 2016, Volume 82, Issue 6, pp 969–974