Blackfish and killer whales in sea world

I think black fish and killer whales shouldn’t be kept in captivity. I belive this because the killer whales and other animals that are kept in captivity are hurting themselves because of depression. Although they live in a pretty big space it’s just not enough for them they migrate they just need a descent amount of space to survive. The reason I belive this is becuase in the articalmit states  that the reason the trainers were killed by the orcas was because of there stree of being kept in small spaces (for them) and living there for there whole life no being able to learn how to catch prey like any other free living orca. Another reason is because of depression, you may not understand. Let me explain, the orcas at sea world would get depressed because of them not getting enough contact with others.