As many as 100,000 marine mammals die each year as a result of ingesting plastic, and members of over 50 species of seabird, many already endangered, have died after ingesting plastic pellets. 100 million lbs of plastic trash enter the world's oceans each year, not including lost fishing nets and other gear. The 70,000 ships in the world fleet dump up to 640,000 plastic containers daily, about 10% of the total, as part of the six million tonnes of solid waste attributed to ships each year.
It is estimated that 8m tonnes of plastic waste finds its way in to the ocean each year. Plastic is notoriously difficult to remove cannot be destroyed (except by incineration). The impacts are increasingly apparent: great rafts of plastic are congregating in ocean gyres, blame games have broken out between neighbouring countries, and marine species face poisoning from the associated toxins. There may even be direct risks for humans, especially the 400m or so poor people who depend critically on fish for their food; nano-plastics are in most marine food, especially filter feeders like mussels and oysters.
There will be a greater weight of plastic than fish in the world's oceans by 2050.