The following is a list of books you can find at the Fishing Librarian and what they cost.
Title
Diving
Leptiod Scales Lore
Placoid Scales Lore
Plate Scales Lore
Resistance Swimming
Skill
Movement
Material Lore
Material Lore
Material Lore
Movement
Cost
2g 50s
10s
50s
2g 50s
2g 50s