Shark Shield Issue

[covert]

I have a shark shield issue of a different nature, this is not a debate if they work or if they dont, I think we can reliably say that they do at least on great whites.

Now im South African and we have GW's by the 100's patrolling our waters especially at some of my favorite diving spots. Now the theory is that when using a shark shield the electrical current can attract the shark to come in for investigation and then repels it once it gets too close. Or at least this is a believe amongst local Spearo's. And truth be told I share that opinion.

So we have an unwritten rule amongst the local brethren: If one individual doesnt have a shield nobody uses theirs.

Tonight I sat down with playing with my baby and I got to thinking about this. I actually have a problem with this arrangement. I bought the shield at great cost for my safety and so that I don't get killed or maimed and cant look after my family. And therefore I believe that if you don't have a shield you shouldn't dive with individuals that have one. And not the other way around.

Now the argument stands that you can leave the shield off and turn it on when necessary, and my problem with this is that viz is generally bad in Cape Town 5-10m sharks can sense and even see prey at much greater distances than that and generally stay out of sight before the attack, so by the time you spot the shark your probably in its jaws already.

On the flip side these guys are my buddies and I don't want to bring them into harms way if I can help it in any way. And to compound to the problem this is the time of year that sharks move in from seal island towards the coast, so their numbers increase in the shallows tremendously.

What do you guys think is the appropriate action or solution.

 

[wax63]

Speaking as a father and a husband - do everything you can to protect yourself and your family.

I would wear your shield, but do your part for the safety of the divers without shields by telling them of the possible dangers of them not wearing a sheild around divers that are. If they make the decision to continue without a shield, then they have accepted the risk and you have done your part.

 

[capetownguy]

hey man, i still wear mine whether i dive with others or not.....i got the 2 hour battery pack on mine...so when im in the kelp i switch it off and soon as i leave it , the shield goes on!

 

[deep thinker]

Being another user of the sheild, I agree with you. The reason we got it is because of the possible protection it provides and yes we did spend big bucks on it. I dont think we should be putting ourselves at risk for the sake of others allthough I would not like to be the one having to call up a freinds wife or family to tell them their loved one has been mauled.
Its not fair to the ones who have it to have to not wear it when others in a group does not use one. I think they should get one or like wax said be willing to take the risk...
On a side note I guess being freinds with divers and so on at some time or another hopefully never you mite have to make that call, be it mauling or drowning, accidents happen

 

[Marwan]

Wear it if it makes u feel safer. If yr buddys dont approve, convince them to buy ht, maybe u could get a group discoumt i dont think it attracts sharks, but it sure zaps yr buddys if they get too closerofl

 

[covert]

The theory behind the attraction as far as i understand works like this.

Sharks have receptors that can pickup minute electronic signals. a sixth sense if you will. Apparently this is so sensative they can pickup the movement of blood through your organs.

So the theory goes that if you throw a device in the water that generates allot of current, the shark will pick this up where it would normally just swim past if it could not see or smell you. The current interests the shark and it comes in close to investigate. Then obviously it enters the radius of the shield and then gets scared off.

Well in theory at least.

 

[Capespearo]

Hey Covert,
I part agree and part don't agree.How far do you think a shark can detect the field ? (I know they can "smell" quite a distance).And if it is not too great a distance,would they not be attracted by fins flapping on the surface,a fish struggling on a spear etc. and come take a look anyway?
I had the old Shark POD which became too cumbersome to dive with and never upgraded to the new Shield,as I would now rather only dive in good vis or in areas that I consider "safer" than others.Friends of mine wear Shark Shields with me in the water and I respect their choice to do so,if someone doesn't want to dive with you because of this,I guess he can be the dedicated buggy boy for the day

 

[Victor Reyes]

The best shark shield ever is to use the necessary precautions and dive in clear water safe waters. Study your diving sites, know your surroundings. most of the shark attacks occur because of false identification of pray item.

Victor Reyes
Spearshark32

 

[deep thinker]

I think most posts here as some merit to it...
Victor like it was said earlier we dont very often get waayy clear water here, best viz I ever experienced on a dive was 30m and that was 5miles from the coast. Like Covert said good viz is 10 to 15m if your on a shore dive. Also most of our areas here can have sharks, thing is you never know when one mite be passing your area of diving.
About the attracting sharks issue, I spoke to a researcher and dive operator in Mosselbaai the other day and they say sharks in the area can feel the vibrations your spear makes when it leaves the gun. So if they can feel that then I dont really see how a pod will make a diverence...
Wear em proudly I say rofl

 

[capetownguy]

hey, see the news? sharks on the increase in false bay...hehehehe
they say that every year when summer comes cos the sharks move inshore...they've seen two between fishoek and strandfontein in the past few months.
got hold of rabitech cos i lost my shark shield charger...apparently a new one is R1170!

 

[deep thinker]

rofl rofl rofl rofl Better start searching harder then buddy. Thats a kak one

 

[covert]

lol yeah a 1k for a charger is hell of allot,,,,,,, and thanks for everyone's tips. DT myself and CTG are well aware of the dangers of sharks, and diving in optimal conditions. Though this being South Africa optimal conditions mean pretty much nothing,,, thanks to our abundance of Great Whites. They hunt and patrol our entire shoreline. Obviously we don't risk diving in too unclear water but that said. 8m Viz wont help you too much when a GW appears from nowhere lol. And the Irony is all the good shoredive spots have been turned into reserves down here. And those that aren't reserves are frequented by GWS. I think they don't want us to shoot fish and if possible have all spearo's malled and killed by sharks ... Thank you government and the parksboard I feel so loved these days.

 

[capetownguy]

HAHAHAHAHAHAHA Too true!!!! They trying to pick us off one by one!

 

[bluecape]

The best shark shield ever is to use the necessary precautions and dive in clear water safe waters. Study your diving sites, know your surroundings. most of the shark attacks occur because of false identification of pray item.

Victor Reyes
Spearshark32

Hiya Victor

The belief of attacks being 'false ID' of prey item is an old myth I'm afraid. That no longer holds true. Researchers of white shark behaviour, and I'm fortunate to know a few of them that work within my line, have now discovered that White Sharks are hugely intellengent and curious animals. They are well aware that a 'foreign item' such as a surfer, swimmer, divers, spearo's etc are not prey, but an intense curiosity causes them to come in for close inspection. Unfortunately, the only way to 'explore' this foreign object is with the mouth, and in the case of a white shark, an exploritory feel can be lethal. Critter cams mounted on white sharks have shown them swimming up to every object in their path, including paper bags, and stopping for a 'look-see'.
In short, the more time that I'm privileged enough to spend around these animals with researchers, the more I'm learning that they have individual personalities, are super- intellegent, and super curious about everything that pops in for a visit. Much like a pedigree dog would be. And like a dog, they WILL read your body language, your fear and your reactions to them, and react accordingly.

Jeff

 

[deep thinker]

Thanx Jeff that was very informative, Im busy reading a little book called South Africas Great White Shark NHBS - South Africa's Great White Shark - Thomas P Peschak and Michael C Scholl
That I bought from a adventure diving store in Mosselbaai. Pretty interesting stuff
Ps: Im sure we all feel much safer now :t

 

[octopus]

Now the theory is that when using a shark shield the electrical current can attract the shark to come in for investigation and then repels it once it gets too close. Or at least this is a believe amongst local Spearo's. And truth be told I share that opinion.

All discussion seems to be based on this assumption. Electro-static field decreases with the square of distance ~1/(d^2) and is of relatively short range. It means that for 10m field drops 100 times.
I wonder at what range shark can detect the shield. Would it detect the spearo by other sensors long before it detects the shield? Perhaps an email to people who developed the device would be an idea?

 

[capetownguy]

i emailed them and their response is as follows:

Hi Greg

This question is frequently asked and we have answered this in the FAQ’s on our web-site

The dissipation of the field is a given rather than an assumption. The important thing is that our waveform is NOT the same as that given off by the sharks prey, the unique waveform has been designed to enter the Ampullae of Lorenzine which is connected to the brain and thus causes great distress to the shark while it is in the zone; fortunately this has no lasting affect on the shark when it leaves the zone. I find the best way to explain it is akin to a human receiving an electric shock.
Sharks do not swim around with their Lorenzini sense to seek prey, it is used as their last sense in attacking mode to help guide them so the other senses of sight, vibration and smell attract the shark well before the Lorenzini sense.
Our products using this waveform are designed to deter the shark in its investigative mode however stating that in all of our tests and that of the Natal Sharks Board (the originator of the waveform) have shown that in an artificially induced environment (blood and visible meal) we have been able to turn the sharks away even at full charge.

Apart from the controlled testing, the anecdotal feedback from professional abalone divers, recreational and professional divers, kayak fishermen, spearo’s etc is very conclusive of the units effectiveness.
During our testing over many years, we have consistently tried to bring sharks in on our waveform however this has never happened. The common feedback that we have received from the professionals is that since using Shark Shield technology they do not see the number of sharks as previously.

Greg I think what I have written here makes for a good argument against the “myth” of attraction, please feel free to post it where you believe it may help customers feel a little better about using this technology.

Greg thank you for taking the time to help us in our quest.

Regards



Paul Lunn

 

[deep thinker]

So our buddies without one is safe, now all we have to do is keep them off our backs when in a dodgy area rofl

 

[covert]

lol yeah nice one greg add to your rep for that one ...... now for tomorrows homework assignment ...... beer booz

 

[Mr. X]

Not much point having a Shark Shield if you don't use it. Are you sure it attracts sharks in? Sounds like it might be an old wives' tale/urban myth. Maybe you need to work on your pals a bit -- persuade them they should invest in preserving themselves. Maybe they could negotiate a multiple-purchase discount. I have a feeling the shark could take you out before you knew it was there.