There’s been a sea change at SeaWorld.

After years of criticism from animal rights activists, the chain of marine parks announced Thursday that it is phasing out its theatrical orca whale shows and ending its orca whale-breeding program — meaning the current generation will be the theme park’s last.

“It’s a long time coming but a fabulous announcement. It’s a huge step in the right direction,” Phil Kline, senior oceans campaigner at Greenpeace U.S.A., said in an interview with Yahoo News. “It’s a responsible step into the 21st century; hopefully it’s just the beginning of the pendulum swinging that way.”

The public perception of SeaWorld changed dramatically with the release of the successful, critically praised documentary “Blackfish” in July 2013. In telling the story of Tilikum, an orca who had attacked and killed at least one trainer and may have been responsible for two other human deaths, the film made a powerful argument against keeping killer whales in captivity.

Publicity around the film led to a decline in park attendance and a plunge in the company’s stock price. SeaWorld fought back with its own advertising and public relations campaign, but public opinion had shifted decisively against the practice of keeping orcas in tanks.

“Survive and adapt to what the public wants and demands in the 21st century, or this business model no longer works and you are out of business,” Kline said. “They did not do this because it was the altruistic thing to do. This was forced upon them by dedicated activists raising the issue to where it became a global concern [that] affected their bottom line, and they have to react.”

Kline said the story behind SeaWorld’s proposed changes is really about the effectiveness of environmental advocacy.

SeaWorld said that it has not taken an orca from the wild for nearly 40 years, and the majority of their orcas have never lived in the wild and would not be able to survive in the ocean. Therefore, its killer whales will live out their lives in the company’s habitats.

Patrick Ramage, the global whale program director for International Fund for Animal Welfare (IFAW), applauded SeaWorld’s announcement.

“We welcome this move and congratulate SeaWorld on this important step as they end the captive breeding of orcas,” Ramage told Yahoo News. “Orcas are highly intelligent and social animals. Their incredibly complex needs simply cannot be met by a life in captivity. IFAW believes that wild animals belong in the wild.”

The Humane Society of the United States worked with SeaWorld to establish its new policies, which will include an emphasis on rehabilitating distressed wild marine mammals in its facilities.

SeaWorld president and CEO Joel Manby said in a statement that the park is proud of the part it has played contributing to humankind’s understanding of killer whales, but that it is changing with the times.

“As society’s understanding of orcas continues to change, SeaWorld is changing with it,” he said. “By making this the last generation of orcas in our care and reimagining how guests will experience these beautiful animals, we are fulfilling our mission of providing visitors to our parks with experiences that matter.”

In an op-ed for the Los Angeles Times, Manby described what he called the paradox of SeaWorld’s success. When the first SeaWorld park opened in 1964, he said, orcas were feared and hunted. By exhibiting them in shows, the park taught the public to love and admire the animals for their beauty and intelligence, Manby said, adding that SeaWorld needs to respond to “the attitudinal change” that the corporation credits itself with helping to create.

Kline, who worked as a commercial fisherman for nearly 30 years before joining Greenpeace, said he has sympathy for SeaWorld’s perspective even if it amounts to corporate PR spin.

“That original SeaWorld in Pacific Palisades — I visited it in ’65 when I was a young boy. And getting splashed by a killer whale when he jumped out of the tank was one of the most exciting and long-lasting impressions of my youth,” Kline said. “I immediately had a fascination of what else was out there in the ocean. At that age, you’re not sophisticated enough to know the true horrors of what’s going on in front of you.”

Kline said if his own impression is symptomatic of how people have reacted to the orca shows broadly it would be hypocritical to deny what the CEO said.

“Although he said it for PR spin,” he said, “it doesn’t make it any less valid.”