These marine mammals can dive up to several hundred meters and stay underwater for up to half an hour. But whales and dolphins don't stop to perch. They never come to shore, as do seals and sea lions. They are always aware, and always moving. It is almost impossible to maintain a family group in captivity.
Tanks only allow a few strokes in any direction before coming to a wall.
This unnatural situation can cause skin problems. Collapsed fins are experienced by all captive male orcas and many captive female orcas, who were either captured as juveniles or who were born in captivity. In a tank, the environment is monotonous and limited in scope. Sonar clicks, the method by which individuals define their surroundings, have limited utility in such as environment. These animals, who are perpetually aware, have nothing like the varied stimulation of their natural environment.