My fisher is a mage, with a water ele slayer Scrappers. Chain lightning is downight vicious, with the boost to the minor slayers - I can do 200+ to 3 water eles at once, 300+ to 1-2 eles, with the spell, by quickly disarming my pole and arming the book.
Protection, though, is a good thing to cast while fishing, then remove when not needed.