At dusk on the balcony of a Princess Cruise ship, a vacationing couple watched as crew members tossed some twenty trash bags filled with garbage into the sea. Shocked, the couple videotaped the incident and later turned the tape over to the U.S. Department of Justice and the FBI. As a result of the couple’s action, the cruise line was fined $500,000 in 1993.

In some ways, cruise ships mirror American society. Passengers aboard luxury liners consume large quantities of food and beverages and produce immense amounts of waste. For example, on a typical seven-day Princess Cruise, passengers consume a ton and a half of cheese, five-and-a-half tons of meat, and five hundred bottles of champagne. Any leftover food, all of the packaging, and any used plastic utensils must be discarded. Dumping refuse into the ocean is a convenient way to...