Except cruise ships are essential to countries like Finland or Norway. The tickets are reasonable priced only because of cruise passengers, tax-free booze and gambling. Especially Hurtigruten of Norway seems to be financed mostly by American Tourists, while providing essential coastal ferry service. And Finland is basically an island, as it is impossible to establish reliable routes through Russia, because local robber parons invent constantly new rules and taxes.
Mega-yachts are actually most environmental way to be bring million tourists to places to like Nordkapp. There has not been much complaints lately, because modern ships clean they sewage water and fuel exhausts.
What sources there could be? I remember that in the 1980s the indigineous Sami-population was whining about "pollution" of Porsanger fjord. Fish had diseases and crabs were dead. Upon investigation it was found out that cruiseships dump their toilets into the sea upon entering Honningsvåg, because the docking & dumping fees were too stiff. Nothing wrong with fishing nowadays.
