The ocean and all the life of the ocean is in crisis due to massive accumulation of plastics. But most of it does not come from cruise ships. It comes from all the plastic that does not get recycled. I'm guilty too, because even though I take everything I can to recycle center (our un-incorporated area does not have curbside recycling), the center only takes plastics labelled 1 or 2. So 3, 4, 5, and 6 go in the trash. So plastics go in landfills from where they can get washed out in storms. Or it lies on the side of the road and gets washed into a storm drain. Or it goes into a river. Or factories dump plastic wastes into rivers. Most of the plastic in our oceans doesn't get dumped there directly, rivers carry it to the sea. https://www.dw.com/en/almost-all-plastic ... a-41581484
If cruise ships were the problem, it would be much easier to fix, just mandate that they not dump anything in the ocean and bring it back to landfills. But not that simple.