Ken A Posted June 14, 2005 Posted June 14, 2005 NSW scientists will be the first in the world to attempt to breed shark pups in artificial uteri as part of the effort to save the endangered grey nurse shark. Minister for Primary Industries Ian Macdonald said the radical plan will involve harvesting embryos from female sharks in the wild, then raising them in specially constructed artificial uteri in NSW DPI laboratories. The shark pups will then be released into the wild, and monitored to assess their survival rates, growth and movements. Grey nurse sharks are thought to number between 410 and 460 in NSW waters, and could be extinct within 15-20 years. Due to their unusual breeding habits their population recovery rate is among the lowest of all shark species. Combine this with the effects of 100 years of hunting before they were listed as protected in 1984, and it is a race against time to save the grey nurse shark. Each female shark has two uteri, and many eggs are initially released into each at the start of the reproductive cycle. But when the embryos hatch as pups, they begin to eat each other in a process known as ‘intra-uterine cannibalism. This is literally ‘survival of the fittest at work’, but unfortunately it means that, in the wild, each female grey nurse shark produces only two pups every two years - not enough to increase species numbers due to the number of accidental deaths caused by humans. This breeding program is a revolutionary approach that will place our scientists at the cutting edge and will allow us to reverse the decline of this wonderful species. The State Government has committed an initial $250,000 per year to fund this groundbreaking research program. The first phase of the project will involve collecting all the basic reproductive data and biological information needed to construct an artificial uterus. Scientists will then focus on developing artificial uterine fluids and artificial eggs, which the shark pups feed on during gestation. The artificial uteri will be tested using the embryos of non-endangered sharks from NSW waters, to avoid any risk to grey nurse sharks. The next step will be to develop surgical procedures to allow scientists to harvest developing embryos from females in the wild, followed by their in vitro development in the artificial uteri. If all goes well, the final phase will see the developed pups released back into the wild. The State Government will be working in partnership with the Sydney Aquarium, which has donated the use of special breeding tanks at Oceanworld Manly for the research, in addition to their expertise in handling sharks in captivity. Only eight pups have been born in captivity in Australia in the past decade – two of them at Oceanworld Manly. The Sydney Aquarium and Oceanworld Manly already have world-class facilities in place for grey nurse sharks, as well as highly trained animal care staff with extensive experience in shark husbandry. This project also has the support of Seaworld on the Gold Coast, as well as the Victorian Department of Primary Industries and a number of overseas organisations. The breeding program is part of a long-term State Government plan to protect the grey nurse. This includes the listing of 10 critical habitat areas along the NSW coast, which are subject to special fishing and diving rules. Unfortunately it is clear that this alone will not be enough to save the ‘Labrador’ of the sea. The NSW population of grey nurse sharks has reached such a critically low level that it wont be able to recover without some form of intervention. Similar measures have been carried out in the past when animal populations reached critical levels, including successful breeding programs for the endangered cod trout in NSW, and the Mexican grey wolf and Californian condor overseas. But this is the first time a breeding program has been undertaken for sharks. This is an exciting opportunity to use the latest technology and research to bring these special creatures back from the brink of extinction.
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