Some time around 1900, a batch of rainbow trout were released into a lake near the river Wye, just upstream of Bakewell.
These fish subsequently escaped into the river and the result was something amazing.
Though rainbow trout hardly ever breed in a river anywhere else in England in any significant numbers until the present time, the fish settled in the Wye and bred very successfully and anglers fishing the dry fly in the Haddon Estate waters on the river are able to catch pure wild-bred rainbow trout.
The rainbows compete with the natural brown trout though the two species feed in a different way and they seem to have retained the breeding season they inherited from their American cousins.
The rainbows are beautiful fish, especially so since the fishing has been so greatly improved by the current brilliant keeper Warren Slaney who has now got only wild trout instead of a mix of wild and stock in most parts of the river under his control.
One thing that has become obvious is that the way that the incoming sewage that enters the river just below the centre of Bakewell influences the average size of the rainbow trout.
Apart from the mayfly hatch between May and early June, the river does not have a really abundant supply of upwinged waterbourn flies and the trout eat a great number of midges.
Despite the frightening possibility of pollution from sewage effluent, the trout grow to a larger average size at times when midges are super abundant because of lots of sewage discharges.
At times when improvements have been made to the effluent this has been known to cause a drop in the average size of fish.
Anyone who – like me – is fascinated with wild Derbyshire trout should try to hunt down a long-out-of-print book.
Published in 1950 by the London Cresset Press, the book is called The Guileless Trout and was written by the late HB McCaskie.
It includes several chapters that deal with the wild rainbows on the Wye.