Tissue weight-specific microplastics in the pearl oyster Pinctada maxima Jameson, 1901 to assess tourism-related pollutions in the Southeast Asia (Indonesia).

The habitats of the pearl oyster (Pinctada maxima Jameson, 1901) are facing competition from anthropogenic activities, particularly tourism, which is prevalent in the Southeast Asian region. This situation poses a threat to P. maxima, as such activities can lead to the emission of microplastics, a subject that has been little studied. This study aimed to investigate microplastic contamination in the tissues of P. maxima found in popular tourist destinations around Lombok Island, Indonesia. The tissues evaluated included the gills, mantle, digestive tract, muscle, and gonads. The result confirms that the tourist areas have smaller P. maxima individuals in terms of tissue weight and shell size and higher levels of microplastics compared to those from pristine areas. In both tourist and pristine areas, the microplastic concentrations in tissues followed this order: gills > digestive tract > gonads > mantle > muscle. Specifically, the gills of P. maxima in tourism areas had an average concentration of 12.09 particles/g ww, whereas those from pristine sites had 5.23 particles/g ww. The presence of microplastic in the mantle tissue in spite of the quantity indicates the reduced ability of oysters to remove inorganic particles due to the accumulation of microplastics. The predominant shapes of microplastics were granules/pellets, followed by films and fibers, while the most common colors were black and green. This study highlights the negative impact of marine tourism on marine resources. Additionally, it provides guidance on which tissues should be avoided and removed to ensure the safe consumption of oysters.