Two protest groups gathered outside Ocean Park yesterday to support the protection of dolphins and call on the park to let the mammals "retire with dignity". While one group used a model of an injured dolphin to highlight the plight of the endangered mammals, the larger group was part of a new global "Empty the Tanks" movement, which also held events in Britain, the United States, Australia, Canada and Japan at marine parks where mammals are held captive. Organiser Zoe Ng, 44, said the Ocean Park dolphin shows were outdated and served no educational purpose. "The dolphins are confined and don't have rocks, sand or the rhythm of the sea; they are clearly being abused," she said. "Let them retire with dignity, instead of having to do four shows a day." Rather than the shows, people could watch dolphins in their natural habitat by going on a pink dolphin tour, she said. Several dozen protestors also called on the park to stop breeding the mammals and let the park's pod of 19 dolphins live in purpose-built enclosures which more closely mimicked the sea. Ng handed a petition with 1,500 signatures to Timothy Ng, deputy director of the park's conservation foundation, and hoped he would consider the proposal to phase out shows within a few years. An Ocean Park spokeswoman said dolphins and other marine mammals played a key role in the education about and conservation of their species. "While we and the protest organisers hold different positions, we strongly believe the animals help to emotionally connect visitors with nature," she said.