The length of a fish, unless otherwise provided, is defined as the shortest distance between the extreme tip of the tail and extreme tip of the snout or jaw, whichever extends the farthest, measured while the fish is lying in a prone and normal position, except:
The term "fork length" means the distance from the extreme tip of the snout to the center of the fork of the tail.
Wash. Admin. Code § 220-300-110