SeaWorld will end killer-whale shows after years of bad publicity.
The attraction has said the current generation of orcas in captivity will be the last.
Animal rights group PETA welcomed the move, but said the whales currently in captivity should be released immediately.
In a statement, PETA said: "PETA has campaigned hard, and now there is a payoff for future generations of orcas – but today is the day to stop breeding, not sometime later this year.
"SeaWorld must open its tanks to the oceans to allow the orcas it now holds captive to have some semblance of a life outside these prison tanks."