Push to Ban Sharks

[AiA in Atlanta]

Shark Eats Shark

You know what they say. There's always a bigger fish.

And when the fishes in question are sharks, it's bound to make a good photo. A sportsman fishing in waters near Kaiteriteri, New Zealand hooked a decent-sized shark Dec. 28, only to have it end up as bait for a giant.

We're guessing the big one got away.

The photo of the sharks was posted to Reddit Dec. 29 and quickly rose to the social news site's front page.

If you're wondering why the sharks' eyes are white, many sharks have a membrane that sheathe and protect their eyes when they go in for a bite. However, some shark species, such as great whites, lack this membrane. Great whites' eyes roll back in their heads when they bite, according to the Smithsonian.

It's not uncommon for sharks to prey upon each other, but it's seldom caught in such dramatic fashion. Of course, there are exceptions.

In May 2012, video of a 16-foot hammerhead shark eating a 6-foot blacktip shark in Florida waters went viral, getting more than 1 million YouTube views. (Warning: Video contains strong language.)

In 2009, the Daily Mail reporte

[Aussie]

Only great whites do that as far as I know, and only when they are in seal hunting mode. Most sharks will check you out then have a tentative taste, or not.

I assumed it was the the great whites in hunting mode that you would most want to deter with the striped wetsuit...

If there was any basis for it Mattus, do you not think that every surfer on the Planet would be wearing stripes?

[freediver]

Have you no sense of style Aussie?

I think bull and tiger sharks are a bigger problem, especially in warmer areas. Even most great white attacks are not like the ones where they leap out of the water from below with the seal in the mouth. They are a gentle, tentative bite. That is why there are so many shark attack survivors.

[Aussie]

That is why there are so many shark attack survivors.

From what specific shark attack? Where are the stats?

[freediver]

All of them Aussie. That majority are non-fatal, regardless of species. You may have trouble finding rigorous stats as the sharks don't line up for identification after biting someone. It is also a bit hard to define what constitutes an attack.

[Aussie]

Okay, as I thought.....this......

I think bull and tiger sharks are a bigger problem, especially in warmer areas. Even most great white attacks are not like the ones where they leap out of the water from below with the seal in the mouth. They are a gentle, tentative bite. That is why there are so many shark attack survivors.

.............was just your usual bullshit.

[harvey]

Gillard is to blame for the (increase in reported) shark attacks, as after all Gillard was meant to be Building the Education Revolution.
So why hasn't the ALP educated the sharks to:
a) recognise humans and,
b) not to attack humans and,
c) hunt outside the flags!!!!!!!!!!!!!!!!
Just another ALP failure.
Can see that there will be a push for the deregulation of Cronulla-Sutherland Sharks Football Club!!!

[Outlaw Yogi]

Sharks are instiktively scared of banded sea snakes.
Meant to have a black & white striped wetsuit made years ago.
Some one beat me to it .. but it works all the same.

Does it work, though?

Apparently yes, according to both divers and surfers who've tested it.

[Sharks are visual hunters surely. But they hunt from below. a striped wetsuit surely won't make any difference to your sillhuotte when seen from below.

Tests I saw showed sharks moving in close, then quickly darting away once the stripes/bands became visible.
Colours apparently make quite a difference too. Bright colours like red, orange, yellow seem to be targeted, where as green and blue seems to be ignored.
It is believed all black wetsuits resemble seals and surfboard + surfer silhouettes resemble turtles, but it's still speculation.

[Edit: even these photos are misleading because the shark won't see colour.

Tests imply otherwise.

There's also electric shark repllant - small pulses from a battery - which according to rumour works quite well too.

[freediver]

It's surprising how quickly the shark shield idea spread compared to the stripey wetsuit thing, even if you do electrocute yourself occasionally.

[Mattus]

Apparently yes, according to both divers and surfers who've tested it.

I question the rigour of this testing. This sounds like a snake oil tiger repellent.

Tests I saw showed sharks moving in close, then quickly darting away once the stripes/bands became visible.

If these are the same tests I saw, they were performed under water, not on the surface, and the shark behaved exactly the same with the unstriped control.

Colours apparently make quite a difference too. Bright colours like red, orange, yellow seem to be targeted, where as green and blue seems to be ignored.

....

[Edit: even these photos are misleading because the shark won't see colour.

Tests imply otherwise.

Despite plenty of ill informed websites stating the opposite, early vertebrate neurobiologists in Western Australia have shown that sharks are biologically unable to see colour. However, this is not inconsistent with sharks being unable to distinguish some colours, like green and blue, from their backgrounds.

There's also electric shark repllant - small pulses from a battery - which according to rumour works quite well too.

While sharks do have electro receptors and can therefore sense these fields, the part of their brain which processes this information is relatively small, while the visual and olfactory centres are much larger. This suggests a visual or olfactory repellant would be much more effective than the electric repellant, and that a shark would likely ignore a repellant where a more poweful visual hunting cue exists.

It is believed all black wetsuits resemble seals and surfboard + surfer silhouettes resemble turtles, but it's still speculation.

Which would be a very strong visual hunting cue. And the colour of the wetsuit would make no difference when hidden above a board to a hunter striking from below. But as you say this is speculation and rumour.

So much of what you read, and what you have said is speculation. While some may be true, I hope you will support funding some real experts to scientifically evaluate them before relying on the repellents.