Coastal garbage patches in Ashmore Reef, Western Australia

Plastic waste production around the world is increasing rapidly and a major proportion of it ends up in natural environments and oceans. Therefore, it is crucial to assess marine plastic sources, accumulation and impacts to wildlife, economies and human health. Here, we estimate quantities and characteristics of sea surface plastics in two north-west Australian sites: Long Reef and Ashmore Reef. These areas were surveyed with net tows and drone surveys conducted from the 18th of September to the 7th of October 2018. Plastics found were predominantly made of polyethylene and polypropylene films, with a high
proportion coming from international sources. We found zones within the Ashmore Reef Marine Park with very high plastic concentrations, comparable to what has been recorded in the so-called oceanic ‘garbage patches’. It seems that these plastic pollution hotspots are formed within coastal accumulation zones such as fronts and eddies; here we propose to call them coastal ‘garbage patches’. We observed a few animals inhabiting these garbage patches, including fish sheltering in plastic pieces and sea turtles feeding upon accumulated material. This study is part of a broader plastic pollution monitoring program, aiming to characterize sources, distribution and impacts of plastic pollution in the Indian Ocean.