With no end in sight to the Centers for Disease Control and Prevention's cruise industry shutdown, cruise lines say it's a question of survival to bring in new customers.

The president of Carnival Cruise Line, for example, the world's largest cruise line, is making sure everybody hears its warnings that the company will move its ships out of the U.S.

Carnival Cruise Line has the more ships based at Port Canaveral than any other cruise line, so the cancellation of all cruises through June 30 is a big deal.

An even bigger deal is its threat to withdraw its ships from U.S. ports as a result of the CDC's cruise industry shutdown.

"While we have not made plans to move Carnival Cruise Line ships outside of our U.S. homeports, we may have no choice but to do so in order to resume our operations which have been on 'pause' for over a year," Christine Duffy, president of Carnival Cruise Line, said in a statement to USA Today.

The Cruise Lines International Association (CLIA) called the CDC's instructions "disappointing" and "largely unworkable," adding that prior to the pandemic, the cruise industry funded nearly 450,000 American jobs and contributed $56 billion annually.

Carnival's newest ship, the 6,000-passenger Mardi Gras, will stay in Spain. It was supposed to be located at Port Canaveral's new terminal.

Carnival claims that it has laid off  many employees and that its supply chain of warehouses and hotels in Florida has done the same. Meanwhile, the general public can travel on airlines, visit theme parks, and see theaters.

Carnival has not set a date or made concrete plans to remove its ships but says that because it takes time to get back up and running, it is only days away from missing the summer cruising season entirely and it cannot afford to do that.

Other cruise lines have already taken steps to relocate their ships in order to resume operations.

Norwegian Cruise Line announced Tuesday that its official return to operation in Europe and the Caribbean will begin in July. And, just last month, Royal Caribbean International revealed new sailings to Israel, Bermuda, and the Bahamas, while Celebrity Cruises added itineraries to St. Maarten, all with specific vaccine requirements.