John Bailey: It’s nutrients not silvers to blame!

John Bailey and tench

Two great tench caught last year - but one of these is a known fish, going down in weight one season after the next - Credit: John Bailey

I’ve got something to confess.

Whilst I left the Norfolk Flyfishers Club a year back, after nearly 40 seasons, I still get David Shannon’s eternally fascinating newsletters that I would hate to do without every month or so.

His words keep me in touch with a club I have always admired and been a proud member of, but above all, David speaks such good sense. I’ve just read his latest offering about the perennial problem on the club’s lake, algae blooms. I haven’t actually trout-fished on the lake for many a year, but I always watched it closely and, yes, water clarity is not what it used to be for sure. And that’s a bind if you want a trout to find your pheasant tail in a London 1950s fog.

David has suggested that silver fish populations are a significant reason for the lack of water clarity and whilst I know about the science on this one, I don’t agree it will have much or any impact if numbers are transferred. David himself reported that out of four trout he caught recently, three sported scars of cormorant attacks. These two pound fish managed to escape, every winter tens of thousands of silvers do not. I’d be very surprised there are as many silvers in the trout lake now as there were years ago when the water was far clearer and trout were easier to catch - or at least could see the fly. So? What’s going on?

Can I broaden the discussion now to most of the pits I fish in East Anglia? Pre-Covid, which changed my life fundamentally like it probably did yours, I had access to 25 or so pits in the Eastern region. Virtually all of them suffered from almost continual algae blooms as bad or worse than those at The Flyfishers’. Moreover, most of those pits held either few or almost no silver fish, such has been the cormorant impact this century. Lack of clarity and lack of silver fish both! You have to  look at deeper reasons for algae bloom conundrum.

I find it hard to escape the conclusion that nutrient loading is the villain here. By that, of course, I mean the increasing levels of dissolved nitrogen and phosphorous that are leaching into our rivers and still-waters. This comes from a multitude of sources like fertiliser run-off, application of slurry onto fields, farmyard manure, soil erosion, discharges from septic tanks and especially sewage treatment plants. All these influences are exacerbated as our numbers grow and we demand and eat more. Nor is it a case of simply trying to cut back on, say, fertiliser amounts. There is something known as legacy P. That’s the phosphorous surplus in the soil that has built up for many years and will continue to cause problems at the Flyfishers’ lake for many years to come, whatever we do right now.

The number of modern, trendy Citizen Science groups is going bonkers right now. One reason I have been  so impressed by the Flyfishers over the years is because members like Tim Aldiss, Dennis Willis, Roger Gibbons and many more have been alive to conservation possibilities way before it became fashionable. These people have laboured for decades to make water in the Wensum valley better in every way conceivable. That they haven’t had huge success is not down to lack of intelligence, commitment or endless effort, it’s simply because, Canute-like, they could not turn back the tide of nutrient loading.

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I can’t offer much more than this tiny crumb of comfort. Returning to my portfolio of pre-Covid gravel pits, I would say that all of them in 2019 were seeing a downturn in size and condition of the indigenous fish stocks. Tench and bream were by and large becoming thinner and weighing less year on year. I think it’s fair to say that carp sizes have peaked in many still-waters and as for silvers, find them where you can. Pike as a result have generally been losing bulk, in some waters gruesomely so. At least at the Flyfishers the trout are bought in and numbers and sizes can be increased temporarily by wielding a cheque book. This is not ideal, but it’s a quick fix that is unavailable to most coarse waters.

I might have dropped out of the Norfolk Flyfishers, but I  remain a member of the Wild Trout Trust. Director Shaun Leonard recently wrote: “(lack of) habitat improvement remains the single, most widespread reason why rivers across the UK and Ireland are in trouble.” I disagree. Now the damned dredger has largely disappeared, I’d suggest nutrient loading is our scourge today and getting rid of every silver fish in the world will not cure that one.

PS: David, keep me on the newsletter list please!