Continents are a matter of land, not population. Therefore Antarctica is a continent as well.
And suddenly you apparently admit that there are at least 6?
And that 8th "continent" is quite a myth.
There's no doubt that plastic in the ocean is a massive problem, but there are no big islands or patches of plastic in the ocean?
Most of the plastic is broken down into tiny bits (which in fact is a bigger problem than if we has these patches of big parts of plastic)
The pictures of massive areas of waste are either from coastal areas or lakes (your last picture is from Bulgaria, I believe)