Such fish do not have to be large. The scales a 8.75lb sea liced hen salmon I caught on the Avon at Ballindalloch on 1st.May 1982 with very many gill maggots showed she had spawned as a grilse and was 7 years old. 4.1+SM 1. This fish did not have extra gill cover spots as is often the case. P.S. I still have scales from this fish.