It is the elusive “holy grail” for shark documentary filmmakers, but to date nobody has seen great whites mating, nor do researchers know where they give birth.

They are the missing pieces in the shark’s population puzzle for scientists.

Researchers believe knowing how many are born each year may help determine the population size, the effectiveness of protection for the species and shark attack mitigation implications for humans.

Flinders University Shark Ecology Group leader Charlie Huveneers said there was “anecdotal” drone footage that appeared to show a great white giving birth.

A YouTube video shows the possible birth near California in July last year.

“And someone may have seen a birth from an oil rig,” Professor Huveneers said.

“Their breeding is considered the holy grail of footage for film crews, but no one has seen it yet.”

White sharks have been protected for more than 20 years to help the species recover from the impacts of gillnet fishing and game fishing, but mystery still surrounds their breeding habits.

He said white shark recovery had been slow because they potentially only had four to eight pups every two years and females did not reach maturity until they were 4.5 metres long.

Maturity for males is 3.7m.

“What the extent of that recovery is something we don’t quite know but having access to the juveniles and nursery areas can help us in understanding, assessing and quantifying the recovery.”

Research since white sharks gained protection in 1999 has defined two distinct populations in Australian waters, which include: 

• An eastern population of about 5,460, including 750 adults, ranging east of Wilson’s Promontory in Victoria to at least Central Queensland and across to New Zealand
• A south-western population of about 1,460 adult sharks ranging west of Wilson’s Promontory to north-western Western Australia

Researchers had theories about the location of nursery areas in the south-western population, based on sightings of 1.7m sharks, but they did not have documentation of breeding or birthing, with newborns thought to be between 1.2m to 1.5m in length.

Google Maps until recently had pins labelled “shark breeding site” placed at Elliston and at Streaky Bay on South Australia’s west coast — both sites of shark attacks this year.

Google did not provide details or evidence of where its information came from, but the pins were removed following enquiries by the ABC.

“I hadn’t actually seen it until [the ABC] brought it up,” Professor Huveneers said.

“I’m not quite sure where they got these points from but they’re not quite accurate and they’re somewhat misrepresentative of the actual size of some of these important areas for great white sharks.”

He said there was documentation of some nursery areas in Australia based on congregations of small white sharks aged two to three years old.

Professor Huveneers said there were areas in WA and also the Great Australian Bight, Coorong, St Vincent and Spencer gulfs in South Australia that might be important areas for juvenile congregations but so far sightings of the sharks were infrequent.

“There have been attempts to find nursery areas for the south-west populations but it was unsuccessful,” Professor Huveneers said.

The vast area and lack of people in the Great Australian Bight made it difficult to find sharks.

Tags fitted to sharks

The CSIRO said genetic research on juveniles in eastern Australia had provided population estimates but similar data in the south-western population required an expanded tagging effort.

Fitting satellite tags on mature sharks might provide clues to their breeding habitats.

The CSIRO has coordinated the tagging of 210 sharks, ranging in size from less than 2m to more than 5m in NSW, WA and SA.

There have been 480 sharks tagged with conventional tags between January 1974 to November 2006, mostly at Neptune Islands and Dangerous Reef off Port Lincoln in SA.

There have also been sharks tagged with acoustic tags and satellite tags that record their positioning.

Professor Huveneers said the majority of sharks tagged off the Neptune Islands and other islands near Port Lincoln were still immature.

“Over time … if we are able to tag large mature females, we might be able to get a better understanding of where these females might go for pupping or mating,” he said.

“If we see that all the females go to a certain location at a certain time of the year and it is consistently every two years, then that would suggest that it’s linked to a reproduction cycle.”

However, that would still leave the mystery about how, and where, the great whites mated unsolved.