Originally posted by LemonCakes:

Thanks for your help, both of you. I was afraid heavy bait was the answer. The serpent trophies are tough to get, but we want to display all the fish. Looks like we'll be heading into the water at night, in the rain, with hope and a harpoon lol.

The technique I like to use is Fireball diving, weaken a serpent to like 10% or lower with fireballs (The Arbalest works too, but might overkill too soon so or not kill it with its huge damage range). Then for the last hit, dive onto his head while casting a fireball or shooting. You should be able to catch the trophy even in the ocean.

If your trouble is finding them, sail in a straight line at night, half sail or oar power at night, though ideal conditions is storm+night you aren't the CIA and can't control the weather.