Microplastics (MPs) generated from mussel aquaculture in Johor Strait Estuary, Malaysia

Abstract Aquaculture of mussels ( P. viridis ), which often involves extensive use of plastic equipment, is considered a potential source of microplastic (MPs) pollution in the marine environment. However, there remains a gap in knowledge regarding the response of aquatic organisms to MPs, particularly in distinguishing between MPs derived from general anthropogenic activities and those originating from aquaculture equipment. In the present study, the presence of MPs in the tissues of P. viridis was determined. Three types of P. viridis aquaculture systems, including raft, longline and smart system, were investigated in the Johor Straits estuary to examine how different aquaculture practices influence the concentration of MPs particles, focusing on their physical characteristic, including colour, size, and shape. Mussels cultured in commercial aquaculture sites were compared with specimens collected from non-aquaculture (natural) areas. The results showed that 72% of MPs concentration found in farmed mussels, while 28% were detected in wild mussels. Approximately half of the microplastics were 101-500 μm in size. Fragments were the most prevalent shape (73%), followed by fibres (18%), with black being the predominant colour (47%). These findings suggest that aquaculture may be a significant source of MPs pollution in the marine environment.