For better or worse, the era of live cetaceans at the Vancouver Aquarium appears to be coming to an end. 

On Thursday night, following two days of passionate debate from dozens of speakers, the Vancouver Park Board voted unanimously to move toward banning the importation or display of whales, dolphins and porpoises at the popular Stanley Park attraction.

Staff members have been asked to present a draft bylaw amendment to facilitate the change by May 15.

"This is a historic decision following many years of debate about cetaceans in Vancouver," board chair Michael Wiebe said in a statement. "We applaud the valuable work by the Aquarium in public education and conservation and look forward to continuing our strong partnership in the future."

Opponents of cetacean captivity applauded and shed tears of joy after the vote, while Aquarium officials and staff abruptly left the meeting, declining to comment for media.

Park board commissioners said they anticipate their decision could be challenged in court, but they believe the ban is firmly within their mandate. The Aquarium is operating in the park, which on federal land but falls under the exclusive jurisdiction of the board, on a 60-year lease that ends in 2029.

"When the breeding ban was brought up in 2015 the Aquarium threatened legal action," commissioner Stuart MacKinnon told reporters. "We have bylaws on cetaceans now and the aquarium agreed to those bylaws. We are simply amending those bylaws and I believe they'll have to adhere to them as well."

But the Aquarium is also in the midst of a $100-million planned update that includes a $20-million expansion of its beluga habitat – a project that was greenlit by the park board.

MacKinnon brushed off the suggestion the ban could leave the board financially responsible for the money the Aquarium has already sunk into the project, however.

"The Aquarium has known for 20 years that this is a possibility," MacKinnon said. "They chose to go ahead with their expansion plans."

Prior to the vote, the Vancouver Aquarium had already pledged to end its beluga program by 2029, while continuing to keep rescued and non-releasable animals.

On Friday, Aquarium president Dr. John Nightingale released a statement lamenting the decision, which he said will threaten the facility's rescue and conservation efforts.

“While we debated the value of caring for and studying cetaceans, there is no debating that we are experiencing the biggest mass extinction since the age of dinosaurs,” Nightingale said, noting that one or two species are being lost per day.

“The timing and execution of the proposed amendment isn’t yet known, but a ban on displaying all cetaceans at the Vancouver Aquarium will have a deep impact on the research we do and devastate our marine mammal rescue centre."

He did not specifically address the possibility of challenging the board's decision, but did vow to "continue to fight for nature long after this conversation has ended."

An independent report conducted on behalf of the board during a previous captivity debate in 2014 cited 20 peer-reviewed scientific papers conducted on cetaceans in the Aquarium's care.

Of those 20, 15 "provide benefit to free-ranging cetacean management and conservation," while the other five were focused on captive care or husbandry with no direct application to wild animals.

Thursday's decision also raises questions about the fate of the five Vancouver Aquarium belugas on loan to other facilities in the U.S., as well as the porpoise, false killer whale and white-sided dolphin currently in its care.

The board said the bylaw amendment, as currently planned, would prevent the belugas from being returned, but park board general manager Malcolm Bromley said it's possible the language will allow the cetaceans already living at the Aquarium to stay.

"We'll take a look at giving some optional language in the bylaw for either keeping the cetaceans there until perhaps the end of their natural life, up to removing the cetaceans from the park. I just want to make sure we have a meeting of the minds with the board," Bromley said.

The board believes the Aquarium can continue to thrive without keeping cetaceans, an assertion Bromley said is backed up in another report, also prepared in 2014.

"Our analysis… is that aquariums that ceased having cetaceans really didn't see a significant reduction in their revenue, so we absolutely see the aquarium continuing to be a world-class facility," he said.

The commissioners' decision reflected the sentiments of the public that elected them, Bromley added – sentiments he believes were informed, to some degree, by the 2013 documentary Blackfish, which largely focused on the care of orcas at SeaWorld locations in the U.S.

"It did, I think, trigger a new public sentiment that has continued until last night," Bromley said.

The deaths of two belugas, 21-year-old Qila and her 30-year-old mother Aurora, also brought the issue of captivity back to the forefront in recent months, triggering protests at park board meetings and inspiring a new wave of opposition to captivity programs.

On Twitter, Mayor Gregor Robertson said he was pleased to see the decision. “It’s the right time [and] the humane thing to do,” he wrote.