What happened America's cruise lines are extending their involuntary corona-cation -- but this time they're doing so voluntarily. Just before 2 p.m. Friday, the Cruise Lines International Association (CLIA), the trade association representing Carnival Corporation (NYSE: CCL) (NYSE: CUK), Royal Caribbean (NYSE: RCL), and Norwegian Cruise Line Holdings (NYSE: NCLH), among others, announced that "the association's ocean-going cruise line members will voluntarily extend the suspension of cruise operations from U.S. ports until 15 September 2020." As of 2:25 p.m. EDT, shares of Carnival stock are down 5.1%, Norwegian Cruise Line Holdings is down 5.8%, and Royal Caribbean is suffering worst of all -- down 6.3%. Image source: Getty Images. So what If you recall, it was way back in April that the U.S. Centers for Disease Control and Prevention (CDC) last extended its no-sail order forbidding cruise ships from sailing out of U.S. ports before July 24. To date, the CDC has not updated or extended that order. Regardless, observing that "it is increasingly clear that more time will be needed to resolve barriers to resumption in the United States," CLIA members have agreed "to err on the side of caution" and "further extend our suspension of operations from U.S. ports until 15 September." Now what This "extension of suspension" will come at a cost. According to CLIA, each day the cruise industry remains shut down costs the U.S. economy about $110 million "in economic activity." More pertinently to cruise line investors, though, Norwegian Cruise says it is burning through cash at the rate of $110 million to $150 million each month, and has probably fewer than 10 months of cash left to it. Royal Caribbean is burning $250 million to $275 million per month during its shutdown, and Carnival just revealed a $650 million-a-month burn rate. And now, according to CLIA, each of these cruise lines can expect to keep burning cash for nearly two months longer than the most optimistic scenario for their respective returns to service. Long story short? We all probably suspected that the CDC would extend its no-sail order eventually, and that cruise lines would have to remain out of service for longer than that optimistic July 24 scenario. Now, sadly, that out-of-service suspicion has been confirmed, even if it didn't actually come at the behest of the CDC. 10 stocks we like better than CarnivalWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Carnival wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of June 2, 2020 Rich Smith has no position in any of the stocks mentioned. The Motley Fool recommends Carnival. The Motley Fool has a disclosure policy.Source