Temporal and spatial distribution of floating marine macro litter in the offshore waters of the Bohai Sea and Yellow Sea (BYS)

Abstract

The categories, sources, and distribution of floating marine macro litter (FMML) in the offshore waters of the Bohai Sea and Yellow Sea (BYS) in the summer and autumn of 2021 and the spring of 2022 were investigated by visual ship transect surveys based on imaging video. The average FMML density of the BYS was estimated to be 26.09 ± 130.51 items/km². From spring to autumn, the density of FMML significantly decreased, and the hotspot areas shifted from the southern Yellow Sea to the northern waters. The temporal and spatial distribution of FMML was influenced by runoff and coastal current transport. Plastic litter accounted for 97.80 % of all FMML types. Domestic litter accounted for 89.86 % of all FMML sources. This study systematically reports the category, source, and spatial distribution of FMML, and the results provide scientific basis for the treatment of marine litter in the BYS.