Shark Shield(tm) Did you run out and order one?

[james 0]

http://www.cnn.com/2005/TECH/02/21/spark.s...hark/index.html

 

I wonder if by switching the wires around, you can ATTRACT sharks? :-)

 

Cheers

James

[Giles 1]

In Grand Cayman just out from the cuts in the north barrier reef are these two great big devices sunk just by the wall (i will post a photo when i get home)

 

These appeared out there about 4 years ago after Tiger sharks were first seen in the North sound where many snorkelers frequent, no attacks ever happened.

 

Anyways ... these devices I have no idea how they were meant to work .. but they actually seemed to attract the sharks we saw more than ever that year they put them down there .. I think the sharks were like .. wow what is that i dont like over there .. its making me want to go away .. but .. hang on I am the biggest predator here ... no one is scaring me away .. so they went to have a look .. realised stingrays were near by ... and went on in feeding ... really didnt work ... I'd like to see it in action as I dont see how you scare the biggest cat off it's block without a fight .. we have all seen discovery channel and animal planet etc ... all the big guys fight to prove themselves they dont go .. oooooooh he seems scarier than me .. i'm going home !!!!!!!!

 

I dont see extreme discomfort having a long term effect on these predators ... but interesting idea .. but they say that it wont affect any other animals .. dont Rays have this sensor stuff too .. and dont all fish have that linear nerve down their sides .. surely everything with a sonar style device will detect it ? I'm no scientist .. just rambling ... hope the abalone fisherman are safer though .. i do like my abalone .. keep fishing boys !

[3@5 0]

on the similar topic of sounds attracting or repelling sharks, i was on the undersea explorer in osprey reef recently and a california based marine biologist was testing out sounds that were supposed to attract and repel sharks.

 

these sounds work in california, both attracting and repelling the sharks.

when transported to australia, the sounds that were supposed ot attract sharks, attracted the ones at osprey reef as well.

 

however the sounds that were supposed to repel the sharks, in fact ended up having the opposite effect and quite a dramatic effect too, as the sharks tended to be really nervous when they moved in.

 

the sounds she used to repel sharks were based on sounds made by orcas which are a predator to sharks in her area.

 

however,there are no orcas around the GBR, so it seems, and hence the sharks did not know they should be afraid of that sound and moved in to investigate. that was the initial quick conclusion of why the sharks were not repelled.

 

it was quite an interesting test though, and it ended up attracting not just the usual grey reefs, but a silky shark as well. that was the only time the silky was seen during the trip btw.

[james 0]

Hi Paul,

 

I noticed that you have the same camera and housing that I have. Have you used the Sigma 12-24 in the Seacam housing yet? I fashioned a zoom gear for mine and it seems very promising.

 

Cheers

James

[3@5 0]

hey james,

no i have not yet used it with the 1dmkii only with the 10d/jonah combination. in fact i have only used the seacam/1dmkii on 2 dives for now, so i am still very much in learning mode

how did you make the gear? what dome will you use with it?

/paul

[Alex_Mustard 0]

I wonder if by switching the wires around, you can ATTRACT sharks? :-)

 

Nice!

[NitroLiq 0]

Was just looking at the sharkshield website.....all these years folks saying "Secure your dangling assets!" (i.e, regs and whatnot and then you get this with the shark device:

 

The unit is fitted to the lower leg via a neoprene pouch. Attached to the pouch is an antenna housing the two electrodes, which trails unobtrusively behind the user. These two electrodes propagate the field into the water, therefore both electrodes must be fully immersed.

 

"Excuse me Mister....is that a shark shield or are you just happy to see me?"

 

Here's the site with images for anyone interested: http://www.sharkshield.com/detail.php?Product=2

 

What would really suck is if it somehow interfered with your dive computer on a deco dive. :shock:

[derway 2]

I remember seeing these things the first time they came around - I guess the South African version. We always wondered what happens to the other divers in your group, or the next group, who are without the shield... When that annoyed aggessive shark finds something normal to nosh on...

 

Be ready for the photo op!

[pmooney 6]

Here is a link to some footage shot during the early testing stages of the Shark Pod research & development.

 

http://www.scubapix.com/movies.htm

 

Testing was conducted at Osprey Reef over 14 day period. The two divers are myself & Rodney Fox.

 

You can best be the judge of how well it works.......

 

Cheers

 

Peter

[Giles 1]

Ok this is that picture of what they put out by the wall in Cayman to repel the sharks ....

 

 

oh wait is that it ?? hmmm

[Giles 1]

Maybe this was it .....

 

 

Now i was only told that by a friend of mine who worked in the DOE (environment guys) they spent some time putting it in and told us that it was to deter sharks .. I have no idea how this works ... maybe it's like an UW rubiks cube for sharks .. they get confused at how it works just like me and give up and run off in a strop.

[Alex_Mustard 0]

I'm not convinced Giles.

First I don't see any sort of transducer-thing to transmit the signal. Second DM communities around the world are well known for their BS! Go on a dive boat out of Sharm and ask about marine life. You will hear a load of hand-me-down/chinese-whispers marine life facts that are almost entirely bollocks!!

 

Although when I was last at the Sandbar in the late afternoon there was a hammerhead - maybe the shark scarers were lost during the storm!

 

The one part of the story I do buy is the Cayman government funding this - since the average Caymanian is very scared of sharks.

 

I suspect that this is a moored CTD (assessing changes in temp and salinity etc) or something similar.

 

Alex

 

p.s. The first picture is the one that scares me.

[MikeVeitch 0]

Does this mean i can't swim around with a Mahi Mahi head in my BCD anymore?!

[pmooney 6]

Probally - not even if the shark shield is under full warranty !

[Giles 1]

Alex the device whatever it is above looked different when it was first put down, apart from being cleaner there was other stuff ... It also had something floating above it at one point.

Now although i love DM BS ... this came from a DOE mouth .. but then again he was CAYMANIAN and they are well known for their BS .. so I have gone full circle .. it all made sense as they were put in the year after they caught the tigers at sandbar ahem .. i mean 5 miles off the East side. I mean Ahem .. sharks in Cayman .. dont be silly .... ahem ... caymanians fishing illegally .... noooooooo anyways after none of that happenes two of these appeared one by Eagle ray Pass ... and one by um Roberts wall .. both are where the entrances to both stingray cities are ... of course it could also have been part of Guy's stingray tagging ??? but tey were never removed.

 

your water property monitoring thing may sound plausable butis equally boring ... although at these cuts is also where the algae tides drift out over the walls in the summer time .. would make sense to monitor these areas as they are great places to monitor sea water and lagoon water as tide effects the flow. There has been a lot of fingers pointed at the CUC power plant in Cayman for heating up the north sound and making more algae .. i personallydont see the power plant having half the effect or the sun .. but hey hoo

 

and mike ... i thought mahi mahi was out this year and that snapper was in ? maybe parrot fish ... i am out of the loop at the minute.

[Drew 0]

I tried this unit in South Africa before. Does the job so long as the shark is not in feeding mode (frenzy). But then apparently the guy who tried it in a feeding baitball in the sardine run (now why would anyone want to scare off sharks in a baitball?) said they bumped him anyways... usually from behind! I guess the electro-static field can't overpower a ball of 100k sardine's em emissions.

[JoeFreediver 0]

I thought I would share my shark shield observations from the standpoint of a freediving spearfisherman. My first experience with the device was in 1997 off the southern end of the Great Barrier Reef in Australia. One of the freedivers had the South African made Shark POD which was designed to be attached to a SCUBA tank. He created a way to attach it to his upper leg and then there was a cable that ran down his leg and attached to an electrode on the swim fin. It was very bulky and difficult to freedive with. As we were hunting pelagic fish, there were always sharks (silver tips and whalers) around but the sharks would naturally keep a bit of distance from all the freedivers and seldom ventured into the range of the electrical field. Even when a fish was taken, the speared fish was always the focus of the shark activity and seldom the diver. It was hard to judge how the device worked since the silvertips and whaler sharks usually kept a respectful distance anyway.

 

A few years later, the device was better adapted to freediving and a smaller unit was developed that fit onto a vest and an on-off switch fitted to a wrist strap with the idea that it could be turned on in an as needed basis in order to prolong battery life as bluewater hunters often spent many hours in the water at a time. It was an improvement but still too bulky for freediving. It did work though. Got to see another freediver with that model keep some very aggressive dusky sharks at bay off southern Baja.

 

The latest model is produced by an Australian outfit and called the Shark Shield. It can be ordered with a 4 hour battery and has been designed into a very small ankle worn unit with about a six foot leash that dangles off the ankle in order to produce the protective electric field. This unit is much more easy to dive with and I predict it will become more popular with freedivers.

 

Though I have yet to dive with one myself, I have seen all three of the different models work on various sharks while worn by other divers. Last summer, while freediving for tuna at Guadalupe Island off the coast of Northern Baja Mexico, a smallish (14 foot) great white shark approached two freedivers who were preparing to get into one of the inflatable skiffs. After passing his gear up and just before climbing into the skiff, one of the divers with the Shark Shield looked just in time to see the great white approaching him at the surface. As soon as the shark got to within 15 feet of the diver it abruptly turned and swam away. I don't think he was about to be bit by the shark but it's nice to know they turn when they get within the range of the electric field. Interestingly, this diver did get out of the water instead of waiting for his buddy to get a little closer to the skiff and within the protective electrical field. Once the guy with the shield got out of the water, the shark turned around again and followed the buddy not wearing a shark shield all the way back to the skiff and swam under the boat just after the freediver made his hasty exit from the water!

 

The only failure I have heard of was an Australian freediver who was attacked and killed by an oceanic white tip while apparently wearing a charged and functioning Shark Shield but I have yet to see the actual report on the incident so I will withhold judgment for now.

 

If you dive where there are species of sharks that are definitely dangerous, such a device might be worth thinking about.

 

Joe Tobin

Santa Cruz

[shark8matt 0]

. of course it could also have been part of Guy's stingray tagging ??? .

 

Giles -

 

As one of the scientists who participated in the stingray study I can assure you that the Guy Harvey Research Institute had nothing to do with the instruments placed out on the north wall. However, looking at your picture, it looks like a data logger, which includes (as Alex suggested) a CTD, as well as turbidity meter and computer/battery pack tube. The placement of these units may have more to do with being outside the two major cuts in the barrier reef than being near the stingrays. Although Cayman does not have powerful tides, the main flow in and out of the north sound would take place along the two channels and this would be a logical place to put instruments to measure water quality. I worked very closely with the DoE for 2 years and never heard a thing about shark repellents. They always said there weren't any sharks to repel. That remark was somewhat refuted when I met a 10+ foot great hammerhead in the Frank Sound. I have also seen a hammerhead off the north wall and at Sandbar, so while uncommon they are around. Actually, I have also seen nurse, caribbean reef, and blacktips around GC. Add the tiger and at least 5 species can be found there though in rare occasions. That being said, I doubt there will be a run on shark shield sales in GC...

 

regards...

 

- MP