Currently, 159 orcas have died in captivity, not including the 28 unsuccessful pregnancies that didn't result in a live born calf. The annual mortality/death rate for orcas is 2.5 times higher in captivity than it is in the wild. Dolphins in close proximity to humans experience extreme stress which prevents them from resting, feeding or nurturing their their young, yet strange humans are still allowed to swim with and touch dolphins at amusement parks. Whales are kidnapped as babies to be brought to water parks, and the adults that can't be used are killed and sunk to the bottom of the ocean in order to not be found. Once at these parks, the whales are used as breeding machines and are forced to breed up to ten years earlier than they would in the wild. In the wild, less than 1% of whales have a collapsed dorsal fin; in captivity, 100% of males and several females have this. A collapsed dorsal fin can be caused by lack of swimming due to living in a small cage one's whole life, dehydration, illness, or injury. Whale trainers do not have to have any formal background in biology to be hired; most are just enthusiastic performers who have no idea that what they are doing is harmful to these animals. Whales and dolphins often swim more than 100 miles per day in the wild. In captivity, they are enclosed in a space which, to them, is the size of a bathtub. Overnight, whales are kept, all together, in an even smaller space, in the dark. This causes whales to turn on each other, even going so far as to kill each other, a phenomenon never recorded in the wild.
It's obvious that keeping whales in captivity is detrimental. So why do we keep doing it? Why are we allowed to do it? Education? That can be done without showing off flips and tricks. Scientific studies? That can be done in the wild.