Marine litter on the continental shelf and slope/floor in Ulleung Basin of East Sea (Sea of Japan)

Abstract

Marine debris is a recognized global ecological concern. Little is known about the extent of the problem in the East Sea regarding litter distribution and its influence on deep-sea habitats. A quantitative assessment of debris present in the deep seafloor was carried out around the slopes of the Hupo Bank and the Ulleung Basin in the East Sea in June 2015 using the 6,000-meter-class ROV ‘HEMIRE’. We first carried out deep-seabed exploration over two weeks, a total of 9 dives were made from a support ship, the R/V Onnuri, at eight stations with water depth ranging between 194 and 2,080 m. The dive times ranged from 1 to 6 hours, depending on the operating conditions. The objectives of this study were to investigate and discuss: (i) litter density, (ii) the kinds of litter, (iii) the influence of environmental factors on the distribution of litter, and (iv) the impact of litter on benthic communities. Litter was found in all 8 sites in 9 dives. The dominant type of debris was represented by Vinyl materials, fishing gears, plastic objects, cans and glass bottles. Over fifty percent of the recorded debris directly impacted benthic organisms. This work provides a first insight on theimpact of marine debris in the East Sea deep ecosystems and a valuable baseline for future comparisons.