It's wrong. Galvanic corrosion may occur when two dissimilar metals are in contact with one another in the presence of an electrolyte creating an electronic pathway for the movement of electrons. Similarly, if using metals which have a large potential difference, galvanic corrosion will occur faster. The reaction requires dissimilar metals such as aluminum (cathode) and zinc (anode). The electrolyte is salt water. Metal moves from the less noble anode to protect the cathode. Excess anode metal is simply not consumed but ions are definitely not "sprayed" out into the electrolyte as he suggests.
What it has to do with fishing is that some believe an electrically charged boat can attract or repel fish. Any field influence will diminish very rapidly as one's gear moves away from the boat. However, there are many other more important factors that will affect fishing success.