Sharks and Cameras?

[boulderjohn]

The recent incident in Maine in which a shark went after a diver's camera persistently got me wondering. In the article I cited, people surmised that he might have been attracted to the shiny nature of the camera. I am wondering if it might be something else.

I have read that oceanic white tips in the Red Sea will frequently get very curious with photographers, and will in fact push into the cameras with their noses. In fact, the Maine incident, as I understand this, is pretty common with oceanic white tips in the red sea. The visibility there is great, and the sharks have plenty of time to see that they are not dealing with a common food fish, as people were guessing in the Maine story.

I am wondering if it might not be something in the electronics of the camera that is the real attraction. We know that sharks have senses related to this that we don't really understand. Could they be sensing something coming from a working camera that is stimulating these senses?

Here are some other examples of sharks and cameras.
YouTube - Tiger Shark Eats Video Camera... While it's running.
YouTube - Tiger Shark vs Camera

I am nothing remotely close to an expert on this subject, so I hope someone with some credentials can provide some thoughts.

 

[Damselfish]

No credentials, but my husband (with big camera rig) was approached a couple times by an Oceanic White Tip while snorkeling off Hawaii. He hit him on the nose twice with the camera. His theory was the shark found the electrical field or sound of the strobes interesting. He had 2 different strobes and thought that might have made it even more interesting than 2 the same.

 

[diversteve]

From elasmodiver - shark senses:

Photographers (and I can testify to this) may have the unnerving experience of having a shark maul their underwater camera strobes which emit strong electrical fields

 

[Doubler]

It's the magnetic and electrical field emitted by the strobes.
There was a special on the Discovery channel and it showed a diver enter the water with a six foot OWT. The shark was just swimming around him and minding his business. The diver was taking photo's and reached up and turned on his strobe. That shark had that strobe in it's mouth in about one second. They stated that the shark senses the field emitted by the strobe as prey and strikes. I believe them so if a shark starts acting hinky in the water around me I shut off my strobes.

 

[ChrisM]

Yes, I've had sharks go at my strobes. Attracted to electrical fields

There's a video somewhere of a very big tiger shark taking an unnerving interest in a diver's AI hoseless wrist unit. Seeing that cemented my decision never to go hoseless

 

[Matt83]

The sharks are curious. Most of what I have seen the sharks get to close for comfort and people stick their cameras in the sharks mouth thinking if it is going to bite something, beter the camera.

 

[DMDavid]

I've never had such a problem with the sharks that I have recorded but then again they were from the Caribbean mon, so they might just be a little more laid back.

As you can hear in this video of mine the camera does emit a whiring noise that I find annoying but it doesn't seem to bother or attract the sharks, not even my ascent alarm at 00:50.

 

[InTheDrink]

I think there are various things that can excite certain sharks' curiosity, for example:

Highly contrasting colours (e.g. black shorty wet suit, white arms and legs)
Electro-magnetic field from strobes
Other colours and shapes - last year my buddy got a lot of unwanted attention from Oceanic White Tips that really seemed to like his Force Fins. My theory is because they look like fish tail fins. Our guide got even more attention with her white normal blade fins. I was just glad that my head to toe in black made me more the observer than the soon-to-be shark lunch

But strobes do seem to get them (OWTs) excited from what I've seen and heard...not sure about other sharks...most are too scared to get anywhere close...

J

 

[Michael Kazma]

This is an interesting topic for me. It is often quoted in documentaries etc. that sharks are attracted to the electro-magnetic field produced by camera setups. Although it seams this way with larger species, I have noticed in videos and from my own experience that smaller species are not so affected by camera equipment. Is this due to them knowing the field represents a food source different from their diet or too large a food source or is it that their senses are not "attracted" to the magnitude of the field or....?????

My query is why are smaller species of sharks not so inquisitive about the field produced by camera equipment???

 

[spt29970]

I highly doubt that sharks can sense the electromagnetic field from strobes. While it is true that sharks can sense nanovolt electric fields, they can ONLY sense DC fields. So if you put a battery in the water, you can be pretty certain that they can sense it. However, the strobe electronics are electrically isolated from the sea water. In fact, there is a nice big plastic housing around the strobe to keep the seawater out, which prevents any DC connection. Even for those people (like me) that use aluminum housings, there is no electrical path between the camera/strobe electronics and the seawater. So the only fields that strobes could possibly emit would be radio frequency from the charging circuit. However seawater is a good conductor which means RF signals are strongly attenuated. RF can't penetrate more than a few cm in sea water (which is why you shouldn't hold your breath for an underwater GPS any time soon). Besides, there is no evidence that sharks can detect RF.

There is ONE source of electromagnetic radiation from strobes that the sharks CAN detect, which of course is the light flash. I have dove with a fair number of sharks and some, like Nurse sharks, absolutely hate it. Others, like angel sharks or horn sharks don't seem to care.

If sharks are responding to the strobe before the flash fires, I would be willing to be that it was the whine of the charging circuit. They can probably hear it, although compared the noisy racket of roiling air bubbles, it is probably secondary.

By the way, I just got back from a Guadalupe White Shark trip. There are photos at

http://www.flickr.com/photos/drsteve/sets/72157625276451950/with/5129852643/

and from my previous trip at
http://www.flickr.com/photos/drsteve/sets/72157607869293974/