The Vancouver Park Board has voted in favour of amending a bylaw that would effectively prevent any new whales, dolphins and porpoises from being kept in captivity at the Vancouver Aquarium.

The amendments were approved at a meeting Monday evening with only one commissioner voting against the motion. The changes come into effect immediately.

Under the revised bylaw, "no person shall produce or present in a park a show, performance, or other form of entertainment which includes one or more cetaceans."

The previous version had no clause regarding performances, but stipulated that no cetaceans captured or taken from the wild be kept in captivity unless it was captured prior to September 1996, was a member of an endangered species and/or was injured or in distress.

The Vancouver Aquarium's resident false killer whale, harbour porpoise and white-sided dolphin have been grandfathered in and are not affected by the bylaw, except that they can no longer be part of shows or performances of any kind. The trio will remain on display at the facility.

Although the amendments have been approved, there may be legal challenges from the aquarium where staff say they plan to fight the ban every step of the way.

Supporters of the aquarium's displays gathered outside the Stanley Park facility prior to the decision, echoing concerns voiced by CEO John Nightingale that the board's decision could be a death sentence for future rescues.

Wild scene with mostly @vanaqua supporters surrounding park board meeting. Yelling, chanting, audible in meeting room pic.twitter.com/FXETpQufyv — Sheila Scott (@Sheila_Scott) May 16, 2017

And from outside a little earlier... Park board building is surrounded by protestors. Many unhappy with proposed bylaw. @CTVVancouver pic.twitter.com/VwKBnJA2rX — Sheila Scott (@Sheila_Scott) May 16, 2017

Nightingale has said that the ban on cetaceans kept in captivity means animals brought in by its Marine Mammal Rescue Program and deemed unfit for rerelease may be put down. The rescue centre is the only facility in Canada with the resources and experts needed to care for rescued cetaceans, he said.

Nightingale said more than 12,000 people have submitted letters to the park board and Vancouver City Council urging the board to reconsider its position.

At the park board meeting, staff said they were unable to confirm the numbers, but did recieve emails from several who supported the aquarium -- some who felt it should continue to house cetaceans in captivity at the facility and others who agreed with the ban.

A park board commissioner clarified that the bylaw says nothing about rescuing and rehabilitating cetaceans, and that staff will be permitted to continue rescuing animals, they will just not be permitted to have them on display for the public.

"The fear mongering has been particularly distressing when we're being accused of being heartless. Or ignoring science." -Commissioner Evans — Sheila Scott (@Sheila_Scott) May 16, 2017

In fact, the park board has no jurisdiction over the rescue facility, another commissioner said. The amendment only effects cetaceans that would be put on display for the public at the aquarium.

Commissioner clarifies: cetacean ban only on animals kept at aquarium. Board has no jurisdiction over rescue centre -- it's not in a park. https://t.co/aJlxdvUrr6 — Kendra Mangione (@kendramangione) May 16, 2017

And park board chair Michael Wiebe said that when it comes to rescues, cetaceans are best treated in their natural habitats.

The board praised the work of the rescue program, but said that the aquarium has told staff that the vast majority of the 100-plus marine mammals saved annually are eventually released. Those kept in captivity are mainly harbour seals, so the amendments will have little effect on the program, the board said.

The amendments approved on Monday stemmed from the deaths of the aquarium's resident beluga whales in the fall. Qila and her mother Aurora died in November of some kind of toxin, but months of testing failed to determine its source.

The deaths left aquarium staff "heartbroken," but determined to bring belugas back in two years. Prior to the announcement that the park board was mulling a cetacean ban, Nightingale said a $20-million beluga habitat – previously green-lighted by the board – would open by spring break 2019.

The plan was to keep the public display open for 10 years, when it would close to the public but continue to be home to whales that could not be released into the wild. The upgraded habitat is part of a $100-million planned update for the aquarium, but construction has not yet started.

Commissioner commends aquarium on proposal to phase out whales by 2029, but says board differs on timeline: Why spent millions now? — Kendra Mangione (@kendramangione) May 16, 2017

Its 60-year lease on the lot in the park ends in 2029, the same year the public display was slated to close.

With files from CTV Vancouver's Sheila Scott and Andrew Weichel