Yes that's right, a Shark zapper.
Call me crazy, but I saw the Stun Gun circuit and thought it might be modified to
use under water.
Several shark shows were about shark deterrents.
They used a device that created an electric field around the diver.
A metal grid was attached to the back of the diver and a wire connected to one fin.
They did not talk about specifics.
The shark is VERY sensitive to small electric currents.
They can since the electric signal given off when you or a fish contract a muscle,
so it doesn't take much to scramble there systems.
On the other hand I don't know how much it takes to scramble ours.
I was not so interested in the 'Body Field' to deter the approach of the shark but a device
attached to a rod or spear gun to zap them when they approach.
At times they come within 2 feet and that's too close for an 8 foot shark.