Gently does it: this is a little bit like moving an immobile patient from a hospital trolley to a bed, except that, in this case, the patient weighs a ton and a half and has to be shifted by crane.
The patient, Rita, a 12ft, 3,000lb (1,360kg) manatee, or sea cow, is one of the most curious of aquatic animals. She has spent the past 26 years living as a semi-invalid in SeaWorld, the Florida theme park near Orlando, having lost a flipper that had become caught in a crab trap.
However, a recent edict from the US Fish and Wildlife Service has laid down that all manatees in captivity which are capable of living in the wild must be released, which means freedom for about 30 animals held in parks and zoos across the US.
SeaWorld has held 10 manatees – mostly animals recuperating from injuries suffered in collisions with boats – and it has begun the releases. Rita was set free this week, along with a smaller animal, Amber, a 9ft, 1,300lb female rescued in 2001.
Although Rita is minus her flipper, SeaWorld staff determined that would not affect her ability to survive in the wild, not least because manatees are vegetarians, feeding mainly on underwater grasses.
"With manatees, their food doesn't try and get away from them, so they don't have a lot of difficulty getting where they need to be," said Scott Gearhart, a senior SeaWorld vet who helped to supervise the release.
Rita was released into Blue Springs, a state park on the St John's river where a warm-water spring ensures the water temperature stays at a temperature of 23 degrees all year round. In the winter, it is a major attraction for manatees from the main river.
Rita will be tagged and tracked by satellite and closely monitored in her new home. Manatee enthusiasts can follow her daily track online at www.seaworld.org.
Manatees belong to the order of mammals known as sirenians, which contains three species of manatee – found in the Americas and West Africa – and the dugong, which is found in the Eastern hemisphere, from East Africa to the Pacific.
There was also a gigantic relative to the manatee called a Steller's sea cow, which lived off the coast of Alaska but it was hunted to extinction shortly after its discovery in the mid-18th century.
Looking humanlike in certain aspects, sirenians are thought to be the basis of the myth of mermaids.