parr, very young salmon with nine bars that are part of their fresh water camouflage

I recall a book for boys dealing with a group of lads learning how to cope in an English countryside community. Fishing was one topic, but this was fly fishing. It seems that salmon parr are frequently mistaken for trout by the inexperienced but, whereas catching trout was fine, catching young salmon was definitely not the done thing. Unfortunately one of the lads fell into this trap and became very unpopular until he redeemed himself in some way or other.

I wonder if this distinction is still made. There is quite a small number of salmon caught with rod and line in British rivers today; 13,700 in 1997.