Ok, strike this one down as a tall tale (or ‘tail’).

Like I said, unlike the bull shark and others, the extent of a Great White’s ability to tolerate fresh water has not been fully established and they are not known to frequent these types of environments, so I am skeptical that a baby one could have survived for the amount of time necessary for it to reach the size described. I’d be more willing to believe that an adult wandered in by accident.

No matter how it got there, I feel that its chances for survival are questionable. It’s not so much food, but rather whether it will be able to adjust to the metabolic requirements required to maintain osmotic pressure in the freshwater habitat.

Of course this is if the sighting is even genuine. Like Lyndon, I am more inclined to discount this one in absence of any other evidence.

“it’s possible it swam in on a high tide or perhaps it swam in as a baby.”

Considering it is estimated that a great white shark will take approx 15 years to reach a length of 15 ft, that would mean the shark would have to have been there for decades to get to 22ft.

A few years back there was a dead 5ft baby great white shark found in Tuggerah Lake (there is suspected to be a white shark nursery/pupping ground close by) there but a 20 ft plus great white shark? This would have been fully established by now and would have been spotted frequently. You can’t hide a shark that large there, particularly as great white sharks have a penchant for swimming at or close to the surface.

Unless there is more evidence to support this claim, I would discount it.

Tuggerah lake is connected to the ocean some places are only ankle deep but other places are a lot deeper upto 20mtrs depending on the tide.

the mouth of the lake that connects to the ocean is anywhere between 150 - 200mtrs wide.

there are a few caravan parks along the edge with plenty of recreational skiing and swimming areas.

there have been plenty of sharks in there over the last 30 years, but nothing that big. it’s possible it swam in on a high tide or perhaps it swam in as a baby.

Plenty of food for it (from memory there is commercial fishing on the lake) along with pelicans and seagulls etc.

regarding the other shark story; I know Bull Sharks are known for swimming up fresh water rivers and they do tend to be very aggressive. I believe Bull Sharks top the list of ‘man-eating’ sharks.

Apparently these sharks can survive in fresh water for quite a long time due to a ’salt reservoir’ in their bodies that keep their chemistry and electrolytes in balance. I’m not sure if any other sharks can manage this feat or not.

The Aussie shark story fascinates me, it does seem to be MUCH too small a lake for such a large shark, especially if the quote regarding the (lack of) depth is accurate.

The main problem is the difference in osmotic pressure between the internal bodily fluids of the shark and the outside environment. When the bodily fluids are “saltier” than the habitat, there is a large influx of water to osmoregulate. This is taken care of the kidneys at a great metabolic cost to the animal and depending on the creatures ability to adjust, they will either die or make up for the energetic requirements for maintaining osmotic pressure. Many species are known to be capable of this, but the Great White isn’t known to. Although there are cases of Great Whites being captured in brackish water, this species isn’t known to be fond of freshwater environments and I wonder how long it would be able to survive in a lake environment as described here.

Is this all clear? I’m in full science teacher mode here.
Concerning how it got there, it must have swum in through a river estuary, since even long term freshwater sharks, such as the Lake Nicaragua sharks, do not breed in freshwater. It either swam in or was intentionally released there, and considering the high metabolic cost of trying to adjust to a freshwater environment, I’d be willing to bet that if this shark got into the lake on its own, it did so by accident and is trapped. Considering the evidence of Great White’s ability to stand freshwater, I think it is very likely that it may not survive in this lake for long.

Now I am wondering if it just recently got there or been there for awhile…….enough food?