Numerical concentrations of macrodebris and microdebris at four intensively sampled stations in the North Pacific Subtropical Gyre.

Data is from line pattern deployed on August 15, 2009 proceeding west from 34°3.4′N, 141°22.4′W (designated by (2) in Fig. 1). The line consisted of 4 stations of 5 repeated manta tows, for a total of 20 manta tows. The four stations were 18 km apart. Visual transect sampling of plastic macrodebris was performed between tow stations, with macrodebris observations for 9 km on either side of given station assigned to that station. Macrodebris concentrations were not statistically different among stations (Kruskal-Wallis test p>0.05). Microdebris concentration from the net tows were statistically different among stations (Kruskal-Wallis test p = 0.002), which was caused by the difference between station 1 and 3 (Nemenyi-Damico-Wolfe-Dunn test, p<0.001). Microplastic concentrations between the other net tow stations were not significantly different (Nemenyi-Damico-Wolfe-Dunn test, p>0.05).