June 3, 2005
Scientists to Breed ‘Test Tube’ Sharks
SYDNEY, Australia -- Australian scientists will attempt to breed gray nurse sharks in artificial wombs under a plan to boost the critically endangered species' numbers, a state fisheries minister said Friday.
Embryos harvested from female sharks in the wild will be reared separately in artificial wombs designed to stop the ravenous fish from devouring each other before birth in what is known as "intrauterine cannibalism.""This is literally survival of the fittest at work, but unfortunately it means that, in the wild, each female gray nurse shark produces only two pups every two years - not enough to increase species numbers," New South Wales state Fisheries Minister Ian Macdonald said in a statement.
Scientists believe only about 460 gray nurse sharks remain in eastern Australian waters and fear they could vanish from the region altogether within 20 years.
The gray nurse shark, which feeds primarily on other fish and is not considered dangerous to humans, was decimated by overfishing and hunting until 1984, when it became the first shark species to be protected by the Australian government.
However, the species has been slow to recover, and some scientists believe the local gray nurse shark population is already too low to regenerate itself naturally.
Macdonald said scientists would begin by collecting reproductive and biological information to construct the artificial shark wombs, but that experiments would be carried out first on non-endangered sharks to avoid any risk to the gray nurse population.
He said scientists are still in the process of developing techniques for harvesting embryos from the wild sharks.