Grey nurse sharks get artificial uterus

AN Australianfisheries biologist has come up with a novel way to stop endangeredgrey nurse shark (also known as ragged-tooth shark or sandtiger) pups eating their siblings in the womb – an artificialuterus.

Grey nurse shark embryos compete fornutrition within the mother’s two uteruses, with the strong onesgobbling up their weaker kin.

New South Wales Port Stephens Fisheries Institute biologist NickOtway has said that overfishing has endangered the species and the cannibalisticembryos made it difficult for numbers to rebound.

Apparently, the last shark standing in each womb devours any unfertilised eggsduring a year-long gestation, after which the mother gives birth to thetwo pups.

Grey Nurse sharks have a long pregnancy and low birth rate. Man’s predation have lowered numbers of this species world-wide.

Mr. Otway is hoping to fix the problem after a successful trial of acrylicwombs in “birthing” wobbegong sharks, which develop in a similar wayto the grey nurse.

In the trial, 10-month old embryos from a wobbegong were put intofake wombs in a special tank and bathed in a solution similar to thatwhich would be in the mother shark’s uterus.

He and his team will experiment on younger wobbegong embryos beforetrying to replicate the intrauterine solution of a grey nurse and breedpups.

He said the fake womb could potentially increase a grey nurse’s brood to 20.

Otway said he could adapt the device for biologically similarspecies, but he isn’t keen to experiment with artificial humanuteruses.

“That might be possible, but I don’t want to get into it because of the ethical issues,” he said.