A leopard shark in a Queensland aquarium has shocked scientists by being the first in the world to give birth without a male, after previously mating in the usual way.

The shark at Townsville's Reef HQ aquarium, named Leonie, hatched three eggs in April last year, despite being kept apart from male sharks since 2013.

The breakthrough research, now published in Scientific Reports, confirms that no male sperm was involved in the eggs' fertilisation.

The process is called parthenogenesis, which in Greek means virgin creation.

Asexual reproduction in sharks is extremely rare, with only around seven cases recorded.

Leonie hatched three eggs last April without any sperm. ( Supplied: Tourism and Events Queensland )

Leonie is the first that has ever been observed switching to parthenogenesis after having pups the usual way.

All other known cases are those in which the animals have started reproducing asexually from the onset of maturity, without exposure to males during their reproductive lifetimes.

The pups are not clones of their mother, and only have half of her genetic diversity.

Reef HQ senior aquarist Hamish Tristram said Leonie had been separated from the male breeding shark in the aquarium because she was having more offspring than they could manage.

One of the pups which will be studied over six years to see if it takes after its mother. ( Supplied: Tourism and Events Queensland. )

"We are absolutely stunned that it happened and so excited by the whole process," Mr Tristram said.

"People are amazed when we tell them we have leopard sharks that don't need males, a lot of the males get a bit frightened because they think 'oh no, we're becoming obsolete!'"

Asexuality useful strategy to keep population going: researcher

The University of Queensland researchers will work with Reef HQ to study the pups until they reach maturity in about six years, to see if they are able to reproduce sexually themselves.

University of Queensland's Christine Dudgeon said the discovery came as a great surprise.

Christine Dudgeon said Leonie's form of inbreeding was extremely rare. ( Supplied: Griffith University )

"This is an extreme form of inbreeding, and the fact that these animals can survive, at least for short periods of time, with this highly reduced genetic diversity really challenges the way that we think about reproduction," Dr Dudgeon said.

"For the most part we are taught that having sex is incredibly important because it increases our genetic diversity, which we need to be healthy, to combat different pathogens and different environmental conditions, so it's a great surprise."

Dr Dudgeon said switching to asexual reproduction could be a useful strategy to allow a population to hold on in extreme isolation.

"These animals are able to essentially extend the life of that egg, and give these animals a chance to find a mate to reproduce," she said.

"But it's unlikely to be a very good long-term strategy, because eventually they need to mix up that gene pool and increase that genetic diversity to adapt to new and ever-changing conditions."

Leopard sharks have recently been listed as an endangered species, and the researchers hope this could lead to clues to help rebuild their population.