“…However, other than counting the quantity of plastic debris [33][34][35][36], there is no reliable and objective method to monitor the extent of such pollution [30,34]. Plastic debris counting techniques can be easily influenced by differences in the sampling and detection methods, such as sea conditions (wave, wind, sunlight, and so on) and observer experience [3,35,36], causing biases [31,35,36]. For example, in contrast to the results of previous studies [3,6,8,19,21], the quantities of plastic debris in the North Atlantic Ocean and Caribbean Sea during a 22-year period [32] and in the Eastern Pacific Ocean during an 11-year period [37] were reported to show no strong, spatial and temporal trends.…”