This morning while standing with three of my swimming friends in the clear water of the shallows at the southern end of the Apollo Bay main beach (after my morning swim), a small shark about 1.2m – 1.5m (4-5 feet) long appeared and swam around and between the four of us at close quarters. It seemed agile and alert, and was turning a lot as it investigated us. It showed particular interest in my left ankle on which I was wearing a Sharkbanz magnetic shark deterrent band. I placed my left foot close to the shark to test it, and there was zero deterrence. If anything it seemed quite interested in the offering. This shark’s persistence in being completely undeterred was disappointing. It eventually swam off towards deeper water. This was the first broadnosed sevengill shark I have seen. I had only heard them mentioned by local shark fishermen.
This is what the Victorian Fisheries Authority has to say about the species (at https://vfa.vic.gov.au/ ):
‘Stay on the dry side of the glass’ when visiting aquariums seems to be the main message here.
The Shark Research Institute description of this species (at https://www.sharks.org/broadnose-sevengill-shark-notorynchus-cepedianus ) is:
“Broadnose sevengill shark – Notorynchus cepedianus
WHAT TO LOOK FOR
A stout broad-headed, small-eyed shark with seven gill slits and a single dorsal fin situated far back on its body.
COLOR
Pale gray above; white below. Small black spots on body.
SIZE
Maximum size for this species is thought to be 9.5 ft [2.9 m], possibly more. Males mature at 4.8 to 5.9 ft [1.5 to 1.8 m] and reach a length of 7.4 ft [2.26 m] or more. Females mature at 6.3 to 6.8 ft [1.92 to 2.08 m] and reach a length of at least 9.45 ft [2.88 m].
TEETH
Teeth of the upper jaw are blunt and pointed; teeth of the lower jaw are large broad and saw-like with 5 or 6 distal cusplets.
HABITAT
Marine, benthic, neritic on continental shelves from the surface to 150 ft [46 m]. This is a coastal species commonly found in shallow bays.
DISTRIBUTION
Temperate seas.
BIOLOGY
- Prey – Bony fishes, rays and other sharks
- Reproduction – Ovoviviparous. Litters may contain up to 82 pups. Size at birth is 18 to 21 inches [45 to 53 cm].
BEHAVIOR
This is an active, strong shark. It moves inshore at high tide, and retreats off-shore at low tide. Most specimens are seen cruising near the bottom, but they may also be found at the surface. Juveniles are frequently found in shallow water close to shore.
DISPOSITION
Danger to humans – unknown. The shark is aggressive when provoked. In Australian and New Zealand waters this shark is regarded as dangerous.”
I first wore a Sharkbanz anklet when swimming at Thistle Island S.A. a couple of years ago. It was lent to me by a friend who swims and dives there. Big sharks are a reality in that part of South Australia. He has two of these devices and kindly lent one to me to take back to Victoria. Until winter this year, I only wore it when snorkelling around Little Henty Reef. But the winter run of salmon along the gutters parallel to the shore on the main Apollo Bay beach is known to attract sharks from time to time. So I started wearing it then as swimming in the gutters not far offshore where fishermen were at times hauling in salmon as fast as they could repeatedly cast out was starting to feel like swimming in berley. I continued wearing it on my daily ocean swims but today will be its last outing on my ankle.
I had read the Sharkbanz advertising material and some independent research, and there is good evidence that the device deters some species of sharks in some circumstances. I was not aware until revisiting and delving further into the Sharkbanz website today that benthic sharks are not deterred by the device. Yes, the broadnosed sevengill shark is a benthic shark. A benthic shark is one that spends most of its time on the ocean floor. This extract from the FAQs section of the Sharkbanz website (at https://www.sharkbanz.com.au/pages/faqs ) seems clear enough:
My experience today confirmed that the juvenile broadnosed sevengill shark I saw responds (or fails to respond!) to the Sharkbanz device with the same cavalier disregard as displayed by the Wobbegong. But the similarities between these two creatures end there. I imagine that the average diver/swimmer would not rate as “a minor threat” a rapidly approaching 9ft+ broadnosed sevengill shark with zero respect for the shark deterrent device. Obviously the name Sharkbanz was selected because ‘Wobbegong Begone’ would simply be misleading. Further, as names go, I’m not big on wobbegong begone.
The juvenile shark was within a cm or two of our legs when swimming around us. I thought more than once it would brush or nudge my leg. The Sharkbanz website contains this statement as to the range of the device :
Of course none of us felt threatened by our encounter with this inquisitive juvenile shark today. But I’m pleased we didn’t meet a 9ft+ adult version of the species.
As for my personal experience with the Sharkbanz: I have swum, surfed and paddled my surf ski in the ocean for many decades without using any short of shark deterrent device, and I have a 100% success rate at not being eaten, nibbled or nudged by a shark. I have worn the Sharkbanz on my swims in South Australia and for the last 5 months at Apollo Bay, also with a 100% success rate at not being eaten, nibbled or nudged by a shark.
So I propose to revert to a simpler defence against shark attack, one which in fact reduces the risk of being eaten by a shark by at least 50%: swim with at least one other person. I’ve never read or heard of a shark in a group of swimmers or surfers attacking more than one person. Even when a surfer bravely paddles over to assist his mate being attacked (a heroic act reported on more than a few occasions) the rescuer never seems to be attacked. From what I have read, sharks such as the great white appear to select and attack a victim with calculated focus.
It’s about time (possibly even long overdue) to post the borrowed Sharkbanz anklet back to my friend anyway…
Just as a reminder to keep things in perspective. Gaze in awe upon the great white shark in its natural element.
I took this photo a few years ago from a shark cage (I was wearing diving gear) secured to the stern of a boat off Neptune Island in the Southern Ocean below Spencer Gulf in South Australia. It was an unforgettable sight.
South 
Very interesting John. I’d like to see the insides of that device. It sounds like they’re claiming a lot from something so small. Generating an electric field, or electromagnetic, or even just magnetic requires a fair amount of energy and an antenna. I’ll look them up.
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Gilbo
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Hi Gilbo, The Sharkbanz website seems to say that the device contains nothing more than powerful permanent magnets.
Cheers,
John
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I’m going to Marengo to camp in February. When surfing there last year I intuitively sensed it was shark territory as in my mind anywhere there are seals, there are sharks. I’ll continue to surf but herd your recommendation of safety in numbers 😳
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My understanding is that the last confirmed fatal shark attack in Victoria was in 1956 (about 300m offshore at Portsea back beach) ….
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A good read, thanks John. I haven’t seen a Broadnose sevengill before. Only small but sniffing around for prey no doubt. Keep an eye out for any seal pups on the reef this season (should be breeding around now). There were some a couple of years ago, but it’s not normally the case. Tim
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Hi John.
A scholarly and entertaining post. In fact, a page turner, were there pages to turn.
I confess to a little envy. Always a privilege to encounter wildlife in their habitat, though I’m with you on the 9 footer. So, your conclusion is that Sharkbanz is a crock? Have always suspected these devices to be overrated. If the big fish is hungry, it will bite anything that looks like prey. The fact that we aren’t to their taste is too late for the faux prey.
I once saw either a seven gill ( they have been hauled out at Waratah ), or a gummy, around a metre, disturbed or seemingly disoriented in a foot or two of water. People near me were excitedly running around and I recall my response being “relax, they call them gummys for a reason”.
I’ve been swimming alone at Waratah for decades. On your theory of solo pursuits, my number may be nigh.
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Thanks Hunto. It is indeed a privilege to encounter various forms of wildlife in their habitat and on their terms. I don’t think the Sharkbanz shark deterrent device is a complete waste of time, but I will be sending it back to the friend who kindly lent it to me, and I don’t propose to buy one. As we have discussed on more than one occasion, I still rate the risk of shark attack in the waters in which we swim as a lower risk than the risk inherent in many other activities we pursue. Cheers, John
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Thanks Tim. I am interested to learn about the possibility of seal pups on Little Henty Reef this season. I will certainly keep an eye out. Cheers, John
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That was a close encounter John! I agree there’s safety in numbers! Cheers Boo 😊
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It was very interesting to have a close look at it Boo. A rare opportunity.
Cheers, John
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