(CNN) — In the first hours after the Carnival Valor set sail from New Orleans on Thanksgiving eve, a brother and sister set off for a place apropos of a holiday mood: They headed to an onboard bar.Announcements echoed through the ship for the missing passenger to check in with guest services, passenger Mike Anderson CNN on Thursday, and people "noticed security starting to search the boat with a photo of the missing (passenger) in their phones."Passengers were told the arrival time to their port of call in Cozumel, Mexico, would be delayed, Anderson said, but no official announcement went out about what had happened.The search extended more than 200 miles in the gulf, Gross said, adding the water temperature there Thursday night was just above 70 degrees -- and somewhat colder in the Mississippi River."The fact that he was able to keep himself afloat and above the surface of the water for such an extended period of time, it's just something you can't take for granted and certainly something that'll stick with me forever," Gross said."