Higher oil prices amid the conflict in Iran have already led some airlines to raise flight prices. Now, cruise vacations could get more expensive too. At least one international cruise line has started adding fuel surcharges to some voyages in order to help cover the elevated cost of oil: Malaysia-based StarDream Cruises announced last week that it will add fuel surcharges to new bookings made after March 20 for its voyages through Asia. The extra fees will be about $19 to $26 per night for every guest age 2 and older, depending on the itinerary, the cruise line said. Experts say it’s possible that cruise companies around the world could implement similar fee structures. And unlike airline fuel surcharges, cruise lines are able to retroactively add fees to voyages that have already been booked. It's not unprecedented: “Fuel surcharges are not a stranger to the cruise industry,” says Leslie Fambrini, a Condé Nast Traveler travel specialist and the founder of Personalized Travel Consultants.…