Additionally, Orcas in the wild eat a wide range of food, from sharks and seals to fish and seabirds. Captive Orcas however, eat dead fish, up to 83 pounds of gelatin, and a valium-like drug. In addition, the water the Orcas live in is too pristine for them to drink due to all the chemicals, causing them to need water supplements in the form of gelatin to prevent dehydration.
Orcas are the ocean's top predator; in areas where they meet Great Whites, they kill Great Whites, so it's no surprise that these captive animals can become aggressive. To combat this sense of aggression, SeaWorld gives their Orcas a valium-like drug to help curb their aggressive tendencies and cure their depression, as some captive cetaceans have tried to commit suicide by throwing themselves over the sides of their tanks. I think it's easy to say that any animal that needs drugs for comfort in captivity should not be in captivity.
Conservation is a large part of the SeaWorld argument. Seaworld claims to have rescued and released over 22,000 injured or ill animals. Many of these animals were species that no other facilities had the ability to care for, such as pilot whales. Some SeaWorld claim that because SeaWorld is one of the largest rescue facilities in the U.S., nothing they do can be negligent. These same people believe that SeaWorld could not rescue animals without captive Orcas' shows, but SeaWorld mainly gets its rescue money from government grants; only about six cents from every 80 dollar ticket goes to conservation efforts.