What is effect of a strobe on a shark?

[Merphotog]

It may very well Not be BS. Please don't forget the second part to the equation. Your disagreement is that the shark's receiver has a small range but look at the transmitter. The "life signal" is very weak. Example: If I shine a little penlight at you underwater it will fade out after several feet. This does not mean that your eyes can only see a few feet away does it. Take a look at the sun. It's a lot farther.....and we won't mention stars.
A fishes bioelectromagnetic signal is extremely weak. It would take an extremely sensitive receiver to pick it up. In comparison to a Gobi a good sized motor could put out a whopping signal.
If you would prefer a more purely electronics answer. I can easily build you a transmitter with battery that will fit in your closed fist. [think little fish] I can show you a receiver [think shark] that can pick up the transmitter up to 50 feet away but then the signal fades out. This same receiver picks up broadcasts from around the world.

In any case.......thanks for the reply.

 

[cudachaser]

A few years back I regularly took my students up to Marineland near St Augustine. They introduced a baby reef shark into the tank and I enjoyed watching it grow over the months. It grew to about 3 ft and was well fed, leaving the other fish residents alone...We'll on one of my trips I found the shark was gone. Asked the trainer what happened...answer, "He died".

When I was packing up after diving the other trainer came up to me and "I gotta tell you the whole shark story...I was trying to take some close shots of the shark...well the strobe fired, he arched his back then rolled over dead"

Joe

 

[iDive Florida]

In response to the question of sharks' reactions to strobes: From my experience working in an aquarium full of sharks and taking many pictures of them up close, my answer would be that a strobe is probably like any other nuisance or point of interest, which most likely sends them in the other direction. The rare cases of sharks attacking a strobe are probably agitation induced. A shark already stressed or in an aggressive mindset might be triggered by this, or any other sudden bright or noisy burst in his immediate area.
Either way it is without a doubt irritating to them just like it is for us, so most will try and leave while a few might eventually share their sentiments with the strobe or its owner!
Like I said, these are just the sharks I've been around in a large aquarium (Epcot Seas Aquarium: 6 million gallons, 203' diameter cylindrical shape, 26' depth to gravel/shell bottom)
Sharks: Two ~10' Sand Tigers, three 5-6' Browns (Sandbar), and a 3' Blacknose.
I hope this helps!
-Ken
NAUI Instructor #47487
Disney Divemaster