Once in the past I mentioned the serious decline in the wild brown trout population in the Lake District and other hill areas. The cause was twofold, in my view.
Firstly, we have seen upland drainage carried to ridiculous extremes (to improve grassland/pasture for sheep). This causes run-off of any rainfall nine times more quickly than previously, leads to ‘badland’ erosion and dislodges delicate ecosystems in the rivers draining the hills.
Secondly, and with the same sheep in mind, the uplands have been fertilised. This leads to excess nutrients in the watercourses, which results in thick growths of algal slime coating the pebbles of river beds. The latter kills off the insect life, which in turn robs the trout of their sustenance.
I noticed last year, however, that the Lake District rivers seemed to have less slime in them. Let’s not beat about the bush in describing this slime: it can be 20cm thick on the boulders, and you’ll have seen similar stuff, hopefully in lesser quantities, when you’ve had a serious bout of flu. It’s not a pleasant subject! Nor is the result very pleasant in our waterways.
This summer there seems to be less slime still and, even as high as 2,000 feet, I found fingerling trout thriving. The numbers were rather low, but as the number was zero three years ago, it is indeed an improvement.
I also noticed rather more dippers this year than I have seen for years. Now, dippers feed on insect larvae that they find under stones: they dive, turn over the stones and catch the larvae before they can escape. The number of dippers indicates a renewal of insect larvae, which also explains why the trout are back. There’s a way to go yet, but things do look promising.
It seems that smaller quantities of fertilisers are now being put on the land. All we need now is an adjustment to the drainage system, allowing the bad practices of the past to decay and silt up, and we may eventually witness the return of a natural ecosystem with wild brown trout instead of stockies.
Talking of dippers, there I was, clambering up this waterfall and intending to peep over the rim to see if trout were in the pool, when this startled dipper surfaced, panicked and promptly flew into a wall of moss, where it stuck! I watched it for a few minutes from a distance of only a few feet.
Then the bird recovered from its dreadful shock and shot past me downstream.
By kind permission of the Cambridgeshire Pride Magazine
Barrie Rickards is a reader in Palaeobiology at the University of Cambridge, a Fellow of Emmanuel College and a curator of the Sedgwick Museum of Geology.
He is President of the Lure Angling Society, Chairman of the Pike Anglers’ Club of Great Britain and President of the National Association of Specialist Anglers.
