A critically injured Chinese white dolphin which was captured by an Ocean Park team last week was given a lethal injection after its health worsened. The park announced the euthanisation of the male dolphin, named Hope by conservationists, on Tuesday morning. Days after reporting positive signs, Hope's condition deteriorated on Monday night, reaching a "humane endpoint", after it began vomiting, breathing weakly and losing buoyancy. Its body temperature also dropped below normal. A decision was made to "humanely euthanise" the mammal, said Dr Paolo Martelli, the park's chief veterinarian. "He was in irreversibly poor condition and further treatment was not a viable option," he added. The Agriculture, Fisheries and Conservation Department said it granted approval for the euthanisation after thorough deliberation with the park's experts. Martelli said it was a difficult decision to make but it was important to end the mammal's suffering. Hope was pronounced dead at 9.22am on Tuesday. While in captivity, Hope had been put on antibiotics to combat infection, painkillers, sedatives and antiemetics. The park also took measures to minimise stress on the mammal. The badly injured dolphin was first spotted in waters off Tai O, Lantau Island, on January 16. It had suffered severe cuts to its tail and back, believed to have been caused by a boat propeller. The worst cut penetrated its spinal column, exposing vertebrae. It had also suffered a broken rib and was unable to hunt. For more than two weeks, scientists and conservationists had been at odds over whether and how to capture the dolphin. Martelli defended the rescue decision saying: "There was no way the dolphin would have gotten better itself in the wild …we believe firmly that this was the right decision made." A team of experts from the park and the AFCD succeeded in capturing the dolphin after 18 days and five unsuccessful attempts. The first rescue attempts took place on January 20. Gary Stokes of Sea Shepherd Hong Kong - who gave Hope his name - said Ocean Park had ultimately made the right decision. "We can all learn from this," he said. "Everybody must understand that the welfare of an animal must come first." Dolphin Conservation Society chairman Samuel Hung Ka-yiu, said the energy now must be focused to ensure the dolphin did not die for nothing and that the remaining 60 were protected. A virtual autopsy will be performed on Hope "to learn all that we can for the care of any future injured dolphins and porpoises in Hong Kong," Martelli said.