Disney could be the hero and save the Killer Whales, even though the entire thing is a crock. As a kid, I had access to the first Killer Whale placed in capacity at SeaWorld San Diego and the original Shamu Stadium. It was a major scientific effort first, and the shows helped pay for the research. It was the original mission of SeaWorld, who opened up the Hubbs research center a year before the park opened. Every marine scientist was for it, and said the SeaWorld's approach was far better than any other aquarium doing it at the time. It also was the first to make major improvements in building new and better facilities for the program.
But while "SeaWorld" has a responsibility under the law to care for every captive mammal under its care until they die, Disney could rebrand, and even move all the animals to a single location, opening up the land to be converted into a non-marine park.
Look at how Six Flags has converted Marineland to Discovery Kingdom in the Bay Area. It can be done.
Point of correction, it was called Marine World not Marineland. It started in 1968 in Redwood Shores (just south of San Francisco) and was owned and operated by ABC (yes that same ABC). It got merged with another animal park of the time called Africa USA to become Marine World/Africa USA in 1972. It was moved to Vallejo in 1986 and in 1999 became part of Six Flags changing its name to the now Six Flags Discovery Kingdom.
https://en.wikipedia.org/wiki/Marine_World/Africa_USA