Virtually all fish react in one of three ways to electricity. They love it, hate it or it immobilizes them. And it works very much the same way. I can't, I don't know how to control the power Captain Kirk. At least no salmon have broken through the force field.
Researchers continue to study how fish react to anode and cathode charges.
Russian scientists studying fish behavior as far back as 100years discovered how fish react to electrical currents. It doesn't take much power to repel the right fish or attract the wrong kinds. Knowing how to harness this power has been the key to success for years among savvy commercial fishermen who know the power of the force and how to properly harness it. The heck with force fields, harnessing the force, having it with you and knowing how to use it is far more important than repelling fish. Downriggers play a big roll in creating and controlling the electrical output of any sport fishing boat.