Researchers say that it could be many more decades before the population has increased enough for that to happen.

Department of Environment, Land, Water and Planning Natural Environment Programs officer Mandy Watson, who is about to publish a research paper on the whales, said there were only about 300 southern right whales that visit the east coast of Australia - of which only 10 females are regular visitors to Logan's Beach.

In South Australia and Western Australia there are about 3000 southern right whales, but that is only five per cent of what the estimated 60,000-strong Australasian population was before whaling began. Almost all of the 60,000 were wiped out with 19,000 culled from the south-east Australian region alone.

"It's still critically endangered," Ms Watson said.

"We're a long way from recovery.

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"The basis for the population in the eastern part of the country is really just a handful of whales that survived whaling."

She said modelling suggests that with Climate Change, the impact on their food resources in the sub-Antarctic region could actually impact the recovery of the population.

Ms Watson, who has been studying southern right whales in Warrnambool for the past 30 years said that there has only been a slight increase in the number of females at Logans Beach.

There has been on average two calves born at Logans Beach whale nursery each year. Some years we have none. The most we have had in one year was seven.

"There has been a slight increase over time in the number of calves but it's not statistically significant," Ms Watson said.

Losing one female, such as famous Warrnambool whale Wilma, from a small population of whales can have a significant impact, she said.

Wilma, who has a distinctive piece missing from her tail, has not been seen at Logans Beach since 2002 after first being spotted in 1982. She has now been found in South Australian waters at the Head of the Bight.

"What needs to happen is we need to start getting females calving regularly at other places like Portland and Port Fairy for the population to really recover," Ms Watson said.

There are signs that this is starting to happen with two females and calves spending the entire season in Portland bay in recent years; one in 2016 and one in 2018. Others have also been found along the coast between Warrnambool and Portland - something that was not recorded back in the 1980s.

She said photo-ID research found that while the whales in Warrnambool use Logans Beach to nurse their calves, currently most of those observed at Portland are migrating whales and most likely part of the larger western population, not the smaller eastern population.

"Despite being the only established nursery in south-east Australia Logan's Beach is actually not really classic right whale over-wintering habitat," she said.

"If you think about the sites where they took most whales from historically, they were big bays like Portland and Port Fairy.

"All the big bays were probably wiped out and a few females that were using locations outside of those areas were the only ones that actually survived that devastation."

Ms Watson said Wilma could have been one of the offspring that actually survived the slaughter.

Port Fairy and Portland were major whaling stations where southern rights were hunted for their oil, which was used for lighting lamps, and baleen, which was used in many products like an "olden days equivalent of plastic".

"They're called the right whale because they were prized by whalers as the best, hence they were the right whale to hunt," Ms Watson said.

"They've got the longest baleen because they've got such a strongly arched mouth and they yielded the most oil."

Ms Watson, who started her research in 2002, said that this part of Australia was historically really important to the species.

She started the South East Australia photo-identification program when she realised that there was a lack of data about whales in the region.

"We already knew then that the population in this part of the country was really small which is why there hadn't been much effort to try and study it," she said.

"It has raised all these questions about why it's so small and, is it recovering?"

Ms Watson is one of only a handful of people in Australia working on southern right whale photo ID research. The current national effort is to bring together three major photo catalogues documenting the movements of individual whales; the south-east Australian catalogue (SEA SRW PIC), Head of Bight catalogue (Eubalaena) and the Western Australian Museum catalogue (WAM).

She said there was a delineation in the genetics between southern rights in the east and the west.

Ms Watson said there was a small proportion - around 10 per cent - of whales in the Head of Bight study that did switch populations, such as Wilma has.

"It is believed this is a mechanism for genetic interchange," she said.

"The mating on the Australian coast appears to be random and opportunistic. They don't pair for life or anything like that."

While it is not clear why Wilma moved on, Ms Watson said it could be that when an area gets too full they move out and look for other locations.

She said she may have also been disturbed by vessel traffic and other noise in the marine environment.

"We don't really know what the impact of underwater noise disturbance is. When they're migrating here from their sub-Antarctic feeding ground they're running the gamut of ships and mining and exploration activity such as seismic surveys," she said. "But it is critical to take a precautionary approach to minimise the risk of disturbance impacting on recovery".

With the first whale sighting of the season in Portland two weeks ago, Ms Watson reminded boat users to adhere to the exclusion zones.

Recreational boat users must remain 200 metres from whales, while high impact vessels, such as jet skis must remain 300 metres away.

Boats that come withing 300m must reduce their speed to five knots.

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