14 January 2009

Diving with Gracie the Dugong announced

To 'celebrate' her twelfth year at the aquarium, Underwater World Singapore (UWS) announced that for the first time, visitors will be able to interact with Gracie.
Photo by Joyce Fang of the Straits Times.

The series of month-long activities include cake parties and dive sessions with Gracie. Full articles on the wildsingapore news blog.

How did Gracie end up at UWS?

According to the UWS website:
Gracie the dugong was rescued from the waters off Singapore’s offshore island, Pulau Ubin, in September 1998 after her mother was drowned after being entangled in a fishing net. A post-mortem of the adult female dugong revealed that she was lactating. The Singapore authorities decided that the suckling calf should be cared for by Underwater World Singapore, as the orphaned calf would not have survived in the wild without her mother to care for her. She has since grown from a 59 kg calf to a hefty 150 kg beauty!

The rehabilitation of our orphaned dugong calf has been carefully documented, one of very few successful rehabilitations of this species in the world. Underwater World Singapore has shared its scientific knowledge and valuable experience by making presentations on our dugong rehabilitation at international forums.
According to a paper "Rehabilitation and display of a stranded Dugong (Dugong dugon) calf in Singapore" by Frederic H.C. Chua, Bruce Mackay, Mark Whitfield, Ee Lin Ooi of the Underwater World Singapore:
On the 25th of September 1998, the Underwater World Singapore staff rescued a stranded Dugong (Dugong dugon) calf from a mangrove area of Singapore, near its drowned mother (2.68m length). A post-mortem examination of the adult determined that she was lactating. The female calf (1.48m length, 61kg weight) was estimated to be six months old, using growth studies of Dugongs carried out in Japan (Toba Aquarium, 1995). Upon approval by the relevant authorities, the calf was moved to Underwater World Singapore, where she was placed into a cylindrical tank (3.8m diameter, 0.82m depth, capacity 9,300L, new seawater inflow at 10mt/hour). She was named ‘Gracie’.

What is the Dugong’s Future?

Option 1: Release into the Wild
  • She would need to be released into an area with suitable and sustainable sea-grass beds, as well as an existing Dugong population.
  • Surveys will be required before and after release.
  • These sites are unavailable in Singapore waters and will therefore require extensive discussions with neighboring countries, including their respective departments regulating CITES issues.
  • Research has shown that the release of other captive marine mammals e.g. Dolphins, are not always successful.
Option 2: Transfer to Another Aquarium with a View to Breeding
  • The aquarium must already house a male dugong.
  • This would provide an opportunity for captive breeding of an endangered species. (As of November 2000, the dugong was about 3 years old)
  • The large size of the Dugong imposes challenges with regard to transportation, temporary holding facilities, welfare, health and funding.
Option 3: Remain at Underwater World Singapore
  • This option provides an excellent platform for broadcasting conservation
  • Adequate healthcare and holding/display facilities must be provided throughout her life (Dugongs are thought to live up to 70 years in the wild).
What was Gracie fed?
From "Rehabilitation and display of a stranded Dugong (Dugong dugon) calf in Singapore" by Frederic H.C. Chua, Bruce Mackay, Mark Whitfield, Ee Lin Ooi of the Underwater World Singapore:
  • The calf was fed on sea grass (Thalassia hemprichii), initially at 11kg per day and subsequently increased now to 15-18kg per day.
  • The sea grass was given to her on rubber “plates” with slits.
  • She was fed milk using an artificial nipple made from the finger of a rubber glove filled with sponge. This was attached via a plastic air-line to an inverted bottle.
  • At approximately 2 years of age, her milk intake was decreased from 300g to 110g per day, to simulate natural weaning.
  • Her weight increased satisfactorily over time at Underwater World Singapore.
  • Composition of Milk Diet
  • 1,600ml Water / day
  • 110-300g Duplex infant formula / day
  • 8.8g Coconut milk powder / day
  • Mixed and given over 4 feedings per day
Are there many captive dugongs?

According to the wikipedia entry on dugongs, Gracies is one of only six dugongs worldwide that are held in captivity. Two are the Toba Aquarium in Japan; one is at Sea World Indonesia, and the last two used to live in Sea World on the Gold Coast, Queensland, Australia, but they have been relocated to Sydney Aquarium.

Are there wild dugongs in Singapore?

Records of dugongs in Singapore waters date back to 1821, but they were considered largely extinct by the 1970s. From Dugongs Disappearing Worldwide Due to Human Overload Environmental News Service 13 Feb 02

Latest sightings of live dugongs in Singapore
Dead dugongs have also recently been seen in Singapore.
Links to more

1 comment:

  1. I am curious as to whether it is possible to breed dugongs in captivity. Gracie is one of the few truly iconic and most recognisable resident of Underwater World, and thanks to her, I'm sure many people now know what a dugong is.

    Given the small size of the captive population, breeding should be encouraged if the aquariums are genuinely interested in the long-term presence of dugongs on display. Breeding will also be supplemented with occasional rescues (wounded or orphaned dugongs that would otherwise not survive in the wild), but breeding should constitute the primary means for the captive population to maintain its numbers. Even if none of the aquariums are willing to give up their dugongs and ship them off to other institutions, the possibility of artificial insemination cannot be ruled out. It is after all, so much easier to transport and handle a vial of dugong semen than an entire live dugong.

    I wonder if aquariums have had any success with breeding the dugong's close relative, the North American manatee...



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