OTTAWA -- A Liberal senator is introducing legislation aimed at gradually ending the increasingly controversial practice of keeping whales and dolphins in captivity.

Keeping the animals cooped up for the sake of entertainment is unjustifiably cruel, said Sen. Wilfred Moore, the architect of the bill.

"In the wild, many whales and dolphins live in large family groups or pods which can grow to over 100 members each," Moore told a news conference Thursday.

"The act of removing a family member and placing the whale or dolphin in a pool in a marine park is bad enough,but the process itself is disturbing and can lead to the death of the animal."

Moore's bill would prohibit captive breeding, imports, exports and live captures of all whales, dolphins and porpoises in Canada, while allowing for the rescue of injured individuals.

With Parliament soon to recess for the summer and a federal election slated for the fall, however, the bill is unlikely to become law.

The legislation builds on a recent Ontario law, which phases out keeping orcas in captivity.

The legislation has the support of the Canadian Federation of Humane Societies, the British Columbia Society for the Prevention of Cruelty to Animals and Zoocheck Canada.

"It is an ethical issue," the Nova Scotia senator said.

Federation CEO Barbara Cartwright agreed it's time to end the practice of keeping marine mammals in tanks.

"It does not meet animal welfare, conservation or education needs," she said, adding that scientific evidence shows that keeping whales and dolphins in captivity causes "physical and mental pain and suffering."

"Canadians do not support the archaic practice of confining and breeding whales and dolphins for the purpose of our entertainment," Cartwright said.

Moore said he hopes to find wide political support for the legislation.

"Bottom line, whales should not be kept in swimming pools."

Currently, there is one orca at Marineland in Niagara Falls, Ont., and approximately 50 captive beluga whales and dolphins split between that facility and the Vancouver Aquarium.