A Canadian senator tabled a federal bill on Thursday that would make it illegal to keep whales, dolphins, and porpoises in captivity.

The Ending of Captivity of Whales and Dolphins Act would expand Canada's existing criminal code provisions prohibiting abuse of animals to ban all acquisitions and breeding of whales, dolphins, and porpoises (collectively called cetaceans). Capturing these animals would be allowed only in instances where they are injured and need help.

"For many Canadians, the practice of keeping whales and dolphins in captivity for entertainment is unacceptable," said Liberal Senator Wilfred Moore at a press conference in Ottawa.

"Treating cetaceans as the highly intelligent species that they are, and ensuring the freedom they enjoy in their natural habitat, is paramount for our own morality."

In May, the province of Ontario made it illegal to acquire and breed orcas — an offense now punishable by up to two years in prison and a fine of up to $60,000.

There are more than 50 beluga whales and dolphins held at the Vancouver Aquarium and Marineland, according to a statement from Moore. Since 1996, the aquarium has captured whales and dolphins from the wild only when they need treatment, but breeding still occurs, according to the CBC.

The only killer whale in captivity in Canada is located at Marineland, an animal theme park in Ontario that has been subjected to fierce criticism and protests since a 2012 investigation by the Toronto Star revealed allegations of widespread abuse and illness among the sea mammals kept there. Marineland has denied it mistreats its animals.

Former Marineland trainer Phil Demers told reporters on Thursday that Moore's law is long overdue. "I support this bill wholeheartedly because it absolutely ensures that future whales and dolphins won't have to suffer the consequences I was witness to," he said at the senator's press conference. "It's my hope that this bill will finally put an end to these cruel practices."

Canada's Green Party Leader Elizabeth May sat beside Moore at the conference. "I know this is fraught issue," she said. "[But] the science is clear that cetaceans are deeply sensitive, social animals and that maintaining them in captivity can never replicate nature."

The proposed legislation has also garnered praise from groups such as the Jane Goodall Institute, the Canadian Federation of Humane Societies, and the director of Blackfish, the 2013 CNN documentary that exposes the dark side of keeping whales in captivity.

In the wake of Blackfish, governments have explored regulating the use of sea animals for entertainment. US federal laws currently regulate how killer whales should be captured and cared for when in captivity.

In February, Washington state senators held hearings about banning the captivity of killer whales for entertainment, according to Reuters.

The California legislature introduced a bill last year to ban killer whale shows at SeaWorld, in San Diego, but it is on hold pending further study.

According to the Born Free Foundation, 63 countries currently hold cetaceans in captivity, with the highest numbers found in Japan.