Yes, disposable plastic straws, cups and bottles are an environmental nuisance and a lot of them end up in the ocean, but few in the media even mention the largest plastic polluter (by far!) – the more than 640,000 tonnes of nylon fishing nets, traps and other debris that industrial fishing fleets unceremoniously dump in the ocean after they become slightly less useful. One study found that as much as 70% (by weight) of macroplastics (in excess of 20cm) found floating on the surface of the ocean was fishing related. Not only that, but millions of sea creatures get tangled in these discarded nets, and most of them die. All of this is the result of the public's voracious appetite for industrial seafood.
Our main source for this meme is nature.com, but some information came from the Guardian.