The keeping of whales, dolphins and porpoises for entertainment – as well as the breeding, trading and capture of cetaceans – has been banned in Canada, following the passing of the "Free Willy" bill this week by its government.

Bill S-203 – the Ending the Captivity of Whales and Dolphins Act – was approved by a wide margin by Canada's House of Commons on 10 June, having already passed through the country's Senate.

Only two facilities still keep cetaceans in Canada, these being Marineland in Ontario, which is reported to have more than 50 beluga whales, and the Vancouver Aquarium, which has one dolphin.

Both facilities will apparently be able to keep these animals, providing they don't breed more, although the situation is complicated by a number of existing pregnancies among Marineland's beluga whales.

The successful passage of the legislation is described as a "watershed moment in the protection of marine animals" by Rebecca Aldworth, executive director of Humane Society International/Canada.

"Whales and dolphins don't belong in tanks, and the inherent suffering these highly social and intelligent animals endure in intensive confinement can no longer be tolerated," said Aldworth.

While dolphins and whales have been popular attractions at water parks for decades, animal welfare groups and marine scientists have increasingly been drawing attention to the negative effects of captivity upon animals that are able to swim dozens of miles a day in the wild.

Incidents such as the killing of a SeaWorld trainer by an orca whale in 2010, which was the subject of 2013's Blackfish documentary, have also made a mark on public opinion. SeaWorld has since agreed to stop breeding and to phase out the use of cetaceans at its parks. The breeding of orcas in captivity has been banned in California since 2015.

Senator Wilfred Moore, who introduced Bill S-203, commented: "We have a moral obligation to phase out the capture and retention of animals for profit and entertainment. Canadians are calling upon us to do better – and we have listened."