Good way to hunt sea serpents?

Usually when I try to go hunting for sea serpents, I sail out into an ocean biome, drive around at speed 2 while looking all around, and usually don't see any serpents until I get bored and head home. Once in a while I'll get like, 3 in an hour. That's not really enough to regularly supplement food with serpent stew.

Anyone have any pointers?

Also, I've never seen a serpent with 1 or 2 stars. Can they spawn with stars?