Uh, not true... A very good group of Atlantic bottlenose dolphins by the names of Striker, Misty, Cocoa, and Breeze and a sealion named Skipper for several years all called Cedar Point home. Saddly each of those 4 are no longer with us...
And they had a nice aquarium next door and it was there I learned penguins literaly stink. And there was Jungle Larry's Safari, even though it was outdsoor vendor it was still in CP.
Worlds of Fun (?) and Knott's Berry Farm housed dolphins however they were rented out. The guy who rented those dolphins out had his full facility destroyed in hurricane Katrina (hence the disppearance of the dolphins Clovis and Echo at HersheyPark) and now has all his dolphins living in the Bahamas.