Cruise ship passengers who sail to Alaska from Seattle or Vancouver will each pay a $50 tax under a new law approved by Alaska voters this week. New taxes also will cover gambling and profits from cruise-related excursions in the state.

The cruise industry spent heavily to counter the measure and is already threatening cutbacks. Carnival says the measure will cost it $24 million in 2007.

It’s the latest attempt in Cascadia to get the booming cruise business to shoulder more of the costs of cruise-related traffic, pollution and tourism services. The bet is that the Alaska business is unique enough and most travelers wealthy enough to pay the extra fee.