I used to work on a fisheries crew where we would use an electro-fisher backpack to momentarily stun small fish (30 - 100 mm length) so we could scoop them up with nets to identify and measure them. The larger fish tended to be stunned for slightly longer because of their larger surface area but I don't imagine this relationship would be maintained for very large animals. Could you electrofish for a blue whale? At what voltage would you have have to set the e-fisher?
So you want to give endangered whales powerful electric shocks. Great! I'm happy to help. This is definitely a very normal thing to want to do.
There are various electrofishing setups, but they all operate on the same general principle: An electric current flows through the water, and also through any fish that happen to be in the water. The electric current, through a few different physical effects, draws the fish toward one of the electrodes and/or stuns them.
For a long time, people didn't really notice that electrofishing injured fish at all. For the most part, stunned fish seemed to be fine after a few minutes. However, they frequently suffer from internal damage which isn't obvious from the outside. The electric current causes involuntary muscle spasms, which can fracture the fish's...