Fisherman's thumbs are callused fingers and can hurt when pressure is applied. normally its caused by Holding too many fish by the mouth.
Remedy 1: O'Keeffe's working hands. I've used it and it works great. If that's not enough, use O'Keeffe's working feet.
Remedy 2: saw this on the internet: Fisherman's Thumb - Bass Thumb, Finger and Thumb Protection
Any other recommendations?