Trout & Salmon Magazine February 2018 Edizione posteriore

THE SECRET LIFE OF GRAYLING
Grayling are believed to have reached Britain before we separated from
continental Europe after the last glacial retreat. There is debate about how many rivers then had populations. The Derbyshire Derwent, Wye, Dove and
Hampshire Avon certainly, Yorkshire rivers including the Wharfe, Nidd, Ure
and Aire, plus possibly the Welsh Dee and Irfon. A Grayling Society study of grayling in the British Isles has found four genetic groups: native Welsh populations and the Annan in Scotland, suggesting grayling may have been introduced to the Annan from a Welsh population; a group containing mostly Northern England populations; a group containing only Southern England populations; and all the remaining populations in the UK.