Subscribe | UPI Odd Newsletter Subscribe Chris Kreis, 19, was fishing with his family off the coast of Captiva, Fla., when they saw a 30-foot, 50,000-pound whale shark swim past the boat. Since whale sharks are gentle creatures, Kreis decided to go for a swim. “I decided, you know what, maybe I should go try and swim with him. I might not be able to do it ever again,” Kreis told ABC News on Monday. Advertisement The intrepid teen described the ride to NBC 2 in Fort Myers: "When I started holding on I felt the whale shark it started moving itself, it felt the drag and it didn't really want me on there so I let go and that's it." Though riding whale sharks is legal, Kreis' actions have garnered criticism from environmentalists. “When people spend a lot of time and a lot of pressure on a fish, it takes away that slime covering and potentially has negative health impacts for the fish,” one marine biologist said. Read More Pope Francis blesses Harley-Davidson bikers in St. Peter's Square Octopus pants? Billy Horschel takes U.S. Open fashion to the next level Michigan man uses turkey baster to rescue baby Delavan turtle beaten to death at golf course Bank clerk falls asleep, makes $293 million error