Putting a Lid on Fish Boxes and Other Foamed Polystyrene Marine Debris Where the murky brown waters of the Pearl River meet the opaque green South China Sea, a trail of floating plastic debris is gathered by the currents as they flow past Macao, Shenzhen, and Hong Kong. I first noticed this floating litter while standing on the deck of a research vessel in 2017, scanning the waves off the western coast of Lantau island for signs of Indo-Pacific humpback dolphins as part of a monitoring program run by the Hong Kong Dolphin Conservation Society. A glimpse of these rare animals was often overshadowed by the foamed polystyrene pollution (also known as expanded polystyrene (EPS) or by the proprietary name Styrofoam) from fish boxes and fishing buoys. And this was not just a problem in the water; as we conducted surveys between Hong Kong’s islands, we passed beaches covered in white plastic, strewn along the shoreline like snow.