Volume-based assessment of coastal litter reveals a significant underestimation of marine litter from ocean-based activities in East Asia

Abstract

Most marine litter monitoring surveys are based on item count, leading to an underrepresentation of larger litter. To better understand significant sources, this study conducted a volume-based marine litter survey in 2020, covering 1% of Taiwan’s 1680 km coastline. In four monitoring periods, a total of 636 m3 of marine litter was detected from which ∼70% stemmed from derelict fishing gear (DFG), ∼20% from plastic bottles and ∼10% from other waste. Survey pictures revealed 66 types of DFG which were compiled into an index. The most frequent items were hard plastic buoys from China and Taiwan. At an average concentration of 877 dm3/100 m, Taiwan showed an extremely high level of DFG pollution. Therefore, this study calls for better domestic waste management practices and the introduction of an extended producer responsibility scheme for fishing gear.