The coastal city of Newcastle is in the midst of a media frenzy, thanks to a string of shark sightings close to popular swimming beaches.
A 15 kilometre stretch of beaches has now been shut for a record six consecutive days, with lifeguards and police craft reporting shark sightings seemingly by the hour. Of most concern have been a purportedly 5 metre, 1,700kg White shark that has been lingering along the coastline; and what is suspected to be a 3 metre tiger shark that was photographed attacking and killing a small dolphin only 50 metres from the shore yesterday (warning: graphic images).
While no attacks on humans in the area have yet been recorded, the sharks have become national celebrities in their own right, with widespread media coverage and commentary. There has even been a Twitter account set up for the @Newy_Shark (which is one account you probably don’t want to be “followed” by).
So what’s the deal here? Are we seeing the real-life return of Jaws? Has a curse been struck down upon the town of Newcastle by Poseidon himself? Is a Sharknado next?
Our resident White shark expert, Barry Bruce, knows a thing or two about these ancient predators. He is one of Australia’s pre-eminent authorities on the species and is the head of our White Shark Research Program. But he is perhaps most famously known for having one of Finding Nemo’s most famous characters named after him.
According to Barry, the story behind Newcastle’s shark saga is far less salacious. Thankfully, we’re not gonna need a bigger blog.
The coastline just north of Newcastle (stretching from the appropriately named Stockton Bight to the even tastier-sounding Seal Rocks) is famously known as being a nursery ground for White sharks. These juveniles are usually about 2-3 metres in length, and a tagging program undertaken by Barry and his team has shown that they are more than prevalent in the area.
Seeing a larger sized White in this area, like the infamous #NewyShark, is slightly less common, but still not at all unusual.
Large White sharks are well known to move up and down the New South Wales coastline, stopping in certain areas when food is prevalent. White sharks have been exhibiting this exact behaviour for countless millennia – it is only when they stop near a heavily populated area like Newcastle that we would notice.
But these are nomadic creatures, and they won’t stay in one spot for too long. We know through collaboration with our colleagues in New Zealand that white Sharks will travel as far north as the Great Barrier Reef – and even across the Tasman to NZ – in a span of just months.
Barry puts the current concentration of sharks in Newcastle purely down to natural variability. Sharks go where the food goes – if there are more sharks in one area at one point in time, it means there will be less in others.
And while we’re in the mood for debunking myths, here’s another one: dolphins are just as much a food source for sharks as are any other species of their size. While it is uncommon for us to observe – and the images were undeniably distressing – sharks are well-known to attack dolphins. Unfortunately, what Flipper taught us was wrong.
More than anything, Barry says that this is a positive advertisement for the health of marine ecosystems in Australia. That there is a large enough food source to sustain shark populations is a good thing, and should be celebrated.
But of course, it is important for beachgoers to take advice from authorities when entering the water. While this is a natural spectacle that should be enjoyed, it is advisable to do so from a distance – and on land. In time it will run its course, and we can all return to the water.
White shark fast facts:
- A common mistake people make is calling these awesome creatures, ‘Great White Sharks’, it’s actually just ‘White shark’ (Carcharodon carcharias). But we still think they’re still pretty great.
- Sharks play a vital ecosystem role as top predators. Declines in top predators can cascade through the food web, seeing some species groups increase while eliminating others.
- We have one of the most comprehensive White shark research programs in the world, with over 250 tagged White sharks in Australian waters.
- Our tagging program provides us with a good idea of migration patterns – we know for example that there is an East and a Southwest population.
- Our research on White sharks is a collaborative project funded under the Australian Government’s National Environmental Research Program.
- We tag these beauties in a very humane way – in a sling, in the water:
3rd February 2015 at 4:51 pm
Sharks are very interesting , especially when they are staying still. Any one who knows sharks knows this is not so. But there is one exception off the east coast off Australia where there is a gully with constant current,with a rock overhang that allows sharks to remain on the same spot where they birth their young.
3rd February 2015 at 4:30 pm
When long-term world shark experts such as Barry Bruce speak, we in the fishing industry listen and accept. In the same way, I listen and accept the scientific advice on the drivers of the climate change which is generally occurring.
Barry is again correct about the history of the Newcastle area. Our dilemma is accepting any hypothesis that the sightings, closures, and attacks in recent years in other areas are consistent with known history, and that ocean swimmers have no real reason to be more cautious than before.
Biologically, white sharks have not been protected long enough to lead to any significant increase in numbers. However, what we do know is that the sharp decline in fishing activity in great white habitat areas has led to a large fall in by-catch of whites. In addition, protection of whites, strongly supported by the fishing industry, has led to a decline in white by-catch.
Logically, there are more great whites in the water, and human ocean users have a right to know that – and when there is a biological increase in white numbers as well, the risk is greater again.
I totally accept that for a casual ocean user, the risk is still extremely low. However, modern society is about good science and transparency. I personally have the odd nightmare about not passing on enough information about issues which may be a threat to others, no matter how small that threat.
One reason that CSIRO and Barry Bruce have been so successful for so long is that they present the facts. In this case, the fishing industry knows what the previous by-catch was – and we know that many previously fearless professional divers are now concerned for their own safety.
This does not lead to any wish to re-trace our steps on protection of whites or to support of the WA measures. What it does lead to is a responsibility to inform the community in a scientific and rational way on numbers of whites and other sharks – and let the community make up their own minds on risks.
3rd February 2015 at 2:29 pm
Any thoughts of the role of amateur fisherpersons and the increase in boats and the practise of burlying to try to attract fish may have on the location of these sharks?
5th February 2015 at 8:56 am
We put your question to Barry. Here’s his response:
“While there is no doubt that berleying attracts fish (including sharks) – after all, that is the point of berleying – berleying only attracts animals that are already in the general vicinity. Depending on the amount of berley, currents or drift of a vessel – this distance can be up to a few kilometres, but typically would be somewhat less. Even in places where berleying is done specifically to attract sharks (e.g. shark cage diving in South Australia) – sharks need to already be in the area if they are to be attracted to the vessel for viewing. Sharks have approached vessels (both recreational and commercial) that are engaged in fishing for as long as such activities have been going on – so this behaviour is not unusual. It is far more likely that the recent increase in observations of sharks in the Newcastle region has been a result of seeing sharks that are naturally moving in and out of the seasonal nursery area in the near-shore and coastal waters off Stockton and the Port Stephens region. The footprint of this nursery area likely varies slightly north or south from year to year due to changes in local currents and the distribution of the fish that these sharks primarily feed on.”
20th January 2015 at 10:34 am
Stockton Beach has long been known by locals as a Great White haunt…some time ago is was something of a fad to land and release sharks (which often drew a crowd of spectators) until it was banned in late 2005. The fisherman would paddle out on surfboards with baited hooks. Not my idea of fun. http://www.smh.com.au/news/national/reeling-in-great-white-sharks/2005/10/22/1129775998728.html
17th January 2015 at 12:26 pm
Thank you for an excellent post. As a West Australian, it is distressing to see the sensationalist coverage of this event. That said, I am pleased that ‘all’ that’s being done at this time is closure of beaches. More concerning are some of the expressions of ‘God given right to swim in the water’. Anyway, here’s hoping, for the GWS’s sake, that it departs soon and the hysteria can die down.
CSIRO, keep up your excellent work. Barry is like a god to us here 😉