Womb with a view to save grey nurse sharks

Scientists have begun working on an artificial uterus to breed the endangered grey nurse shark.

Australian marine ecologist, Dr Nick Otway of the New South Wales fisheries agency is spearheading the work, a new approach to captive breeding.

"It's outside the square, certainly," says Otway who says he dreamt up the idea after his minister asked whether it was possible to breed the animals.

There are fewer than 500 grey nurse sharks in eastern Australia, says Otway.

He says the sharks are sensitive to pressures such as fishing because the animals have so few offspring.

The artificial uterus is aimed at boosting the number of shark babies for release into the wild.

Are sharks cannibals?
Mother grey nurse sharks do not feed their babies in utero because there is no umbilical cord connecting the two, says Otway.

So, to survive, the growing babies eat their younger siblings until there's only one pup left in each of the mother's two uteri.

"It's inter-uterine cannibalism," Otway says.

The plan is to remove the embryos from the mother before they become cannibals and place them in artificial uteri where they can be fed artificial eggs, giving all siblings a chance to grow up.

Are sharks fussy about giving birth?
Otway says his team has been collecting a range of basic information about shark reproduction, including tagging sharks in the wild to collect information on conditions, such as water temperature, they need to reproduce.

The researchers have also been trying to work out what type of material to make the uterus from.

"We have a preliminary design," says Otway.

He says the uterus is likely to be made out of clear acrylic tubing about 20 centimetres in diameter and at least 1.2 metres long, the maximum size of sharks before they are born.

It will be fitted with tubes, pumps and filters to ensure fluids and oxygen are circulated and waste is removed, Otway says.

The final aim is to have a batch of uteri, wrapped in foil to simulate the dark conditions of the normal womb.

The best way to conserve the sharks?
The project has met with mixed response from scientific and conservation groups, which have been concerned about the impact of fishing on shark populations.

The New South Wales branch of the Australian Marine Sciences Association recently wrote to the state fisheries minister expressing concern that such research could "divert public attention away from the issue of protecting wild populations and properly managing critical habitats".

While welcoming funding for the uteri research, it urges the minister to also completely exclude fishing activities from habitat zones.

Associate Professor Andy Davis, an Australian marine ecologist at the University of Wollongong, says building the uteri is more politically acceptable than locking away habitat from fishing.

But, he says, it is an unproven approach and could undermine other more effective ways of conserving sharks.

"Let's say it was 100% successful," he says. "The question is, where are all these juveniles going to go?"

How much is it to cost?
Michael Kennedy of the Humane Society International is concerned about the cost.

"It's a lot of money over a long period of time," he says.

His group is looking at legal avenues to force expulsion of fisheries from shark habitats and he says money is needed to help compensate fisheries for being kept out of areas critical to the grey nurse shark's survival.

Otway says: "You are never going to stop all fishing related mortality."

"You could look at a breeding program as being an insurance policy."

He estimates his project overall will cost around A$500,000 (US$370,000) a year and will take at least 10 years to complete.

Source: abc.net.au/science/news/enviro