A South Korean aquarium publicly apologised Wednesday for the death of a captive whale shark, and said it would release a second such shark following protests from conservationists. \"We admit a lack of proper preparations (for sustaining whale sharks in captivity) and we regret causing concern among the people,\" Aqua Planet, which opened last month in the southern island of Jeju, said in a statement. Whale sharks, the world\'s largest fish, are protected under the Convention for International Trade in Endangered Species. The aquarium said they were caught by chance in a fisherman\'s nets off the southern island last month, about a week before the facility opened. One of them stopped feeding around the end of last month and died last week. The Korea Federation for Environmental Movement of Jeju said the whale shark had died of extreme distress in captivity. It criticised the aquarium for holding the pair in a tank 25 metres (82 feet) long, 23 metres wide and 8.5 metres high, along with some 8,000 other fish. Awareness of conservation is growing in South Korea. Jeju will host a major international congress on the issue next month. In April, a court on the island ordered the release into the ocean of five dolphins which had been captured without permission and used in a circus.