The cetacean ban looming over the Vancouver Aquarium amounts to a death sentence for some of the vulnerable marine mammals found in distress along B.C.'s coast.

That's the argument from aquarium officials who are urging the public to speak out against the bylaw change before the Vancouver Park Board potentially puts it to a vote next month.

The ban would apply to all belugas, porpoises, false killer whales and other cetaceans, even the sick and injured ones that are saved and nursed back to health by the Marine Mammal Rescue Program but deemed unfit for release by the Department of Fisheries and Oceans.

Aquarium CEO John Nightingale said for those animals, being placed back in the wild would mean certain death.

"We are proud and thankful to have a world-renowned rescue program that can have both ongoing care and a new home for these animals that are not capable of surviving on their own," Nightingale said Thursday.

"The park board's actions to date have been short-sighted, rushed and will ultimately undermine the very thing we are seeking to protect: the welfare of dolphins, whales and porpoises in nature."

The vast majority of the 100-plus marine mammals saved annually by the program are eventually released, but some are kept in captivity because their injuries were assessed as too severe or they weren't able to develop basic survival skills.

Whether or not an animal is released is ultimately up to the DFO, according to the aquarium.

Details of the board's proposed ban aren't being shared until next month, so it's unclear exactly how it would impact non-releasable cetaceans, but aquarium officials are already fearing the worst.

"This is the only place in Canada they can live, so there's no other place to send them," Nightingale said. "It's impractical to think about sending them further afield. Some don't transport very well or fly long distances."

Nightingale put out a call to everyone who supports the Marine Mammal Rescue Program to contact the park board and make their voices heard before May 15, when the bylaw amendment will potentially be voted on.

The board issued a statement Thursday afternoon defending the proposed bylaw change and suggesting it won't have a serious impact on the program.

The aquarium's "important work" is being taken into consideration, the board said, as are the three rescued cetaceans currently in its care, Chester, Helen and Daisy. It’s possible those animals will be allowed to stay.

“We applaud the valuable work still being done in public education and conservation and look forward to continuing our strong partnership into the future,” board chair Michael Wiebe said.

Cetacean rescues only represent a "tiny percentage" of marine mammal rescues, the board noted.

Commissioners took a major step toward implementing the ban last month, voting unanimously to have staff prepare a draft bylaw amendment to facilitate the change.

Members of the board said they were reflecting the sentiments coming from the public. The vote followed two days of heated debate, with many opponents freshly outraged from the deaths of Qila and Aurora, the aquarium's two resident beluga whales.

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

The facility ended the practice of capturing cetaceans from the wild more than 20 years ago.

With files from CTV Vancouver's Penny Daflos