California Code, Fish and Game Code - FGC § 8392

No California halibut may be taken, possessed, or sold that measures less than 22 inches in total length. Total length means the shortest distance between the tip of the jaw or snout, whichever extends farthest while the mouth is closed, and the tip of the longest lobe of the tail, measured while the halibut is lying flat in natural repose, without resort to any force other than the swinging or fanning of the tail.