Cientistas Australianos estão desenvolvendo técnicas de gestação artificial em exemplares de tubarões visando a preservação das espécies. O governo e o Aquário de Sidney irão doar U$ 250.000,00 durante quatro anos para o projeto.

Test tubes offer hope against extinction
By Adam Gartrell
June 03, 2005
From: AAP

AUSTRALIAN scientists will attempt to breed the world's first test tube sharks in an attempt to save the grey nurse from extinction.

The groundbreaking breeding program unveiled in Sydney today by New South Wales Primary Industries Minister Ian Macdonald will see scientists harvesting embryos from wild female grey nurse sharks then raising them in specially designed artificial uteri.

The grey nurse, often referred to as 'the labrador of the sea' because it is harmless to humans, was hunted for its skin and liver oil until 1984, when the NSW government placed it on the protected species list.

But commercial fishing accidents, coupled with the grey nurse's extraordinarily low birth rate, have seen numbers continue to dwindle.

Fewer than 500 are believed to remain alive in NSW waters, and experts predict they will be extinct within 20 years unless humans intervene.

The radical plan will attempt to overcome the grey nurse's tendency towards 'in-uterine cannibalism', by which embryos hatch in-utero and feed off each other until only one survives.

Grey nurse sharks hatch more than 40 embryos in two uteri, so two pups are usually born at any one time from the one mother.

By raising the embryos in individual uteri, scientists expect they will be able to see up to 40 pups survive from each female's annual cycle, rather than the usual two.

After artificial gestation, the sharks will be released into the wild where they will be monitored for survival rates, growth and movements.

The NSW Government, in conjunction with Sydney Aquarium, has committed resources valued at $250,000 per year for four years to support the program.

Mr Mcdonald said the scientific community agreed the program provided the grey nurse's best chance of survival.

"The NSW population of grey nurse sharks has reached such a critical low level that we won't be able to boost numbers without some form of intervention," he said.

"We are, we believe, throwing a lifeline to the grey nurse shark ensuring the survival of what is, in effect, the labrador of the sea."

Dr Nick Otway, Department of Primary Industries senior research scientist, has been working with the grey nurse for six years and says the program can succeed.

"The research that we've been doing so far on the wild population certainly says that we're looking at a 10- to 20-year scenario for extinction on this coast," he said.

"So it is time we take this major interventional step to try and ensure it does survive for the future. It's something that we have to do now."