SYDNEY: The endangered grey nurse shark is its own worst enemy, its young eat each other in the womb, so Australian scientists have a radical rescue plan to artificially inseminate and breed the ocean predator in test-tubes. The grey nurse is one of the fiercest-looking but most docile marine creatures, and despite it being declared endangered in 1984 and its habitat protected, it could become extinct along Australia’s east coast within 20 years, scientists say.
In a process called intra-uterine cannibalism, grey nurse embryo pups develop a jaw and razor-sharp teeth very early in their development and cannibalise siblings in the womb.
The sharks have two wombs in which a dominant pup will consume its siblings, leaving only two surviving pups every two years when the shark breeds.
“It is not breeding quickly enough. It is being caught out in the wild and it is not recovering from the fishing pressures on the east coast,” said Melbourne Aquarium curator Nick Kirby.
Nicknamed the “labrador of the sea” due to its docile nature, grey nurse numbers plunged after being wrongfully blamed for many attacks on swimmers off Sydney beaches and it was brutally hunted until the 1960s.
Their plight has now become critical. Breeding programmes have been used to conserve the endangered cod trout in Australia, the Mexican grey wolf and Californian condor, but scientists here say this will be the first attempt at shark breeding.
Melbourne Aquarium this month artificially inseminated Lonnie, a 2.6 metre (8.5 feet), seven gill shark with the sperm from a male tank mate. It will take several months to see the first signs of any pregnancy, but if successful the insemination technique could be used on the critically endangered grey nurse.
“We are using our seven gill shark as a surrogate species because they are more common and easier to work with than risking the grey nurse shark,” Kirby said. A common problem trying to breed sharks in aquariums is their reluctance to mate.—Reuters
