Salmon and Trout Association: Blog

September 2010

The discovery of the killer shrimp (Dikerogammarus villosus to those with a scientific bent) at Grafham Water recently has raised several issues – some good, some bad. The good is that it was discovered by anglers, and I’ll talk more about that later, because it shows the great value of our ears and eyes at the waterside, which could go much further if we play our cards right.

First the bad news. Here is a bug which has marched steadily across Western Europe in the past decade, aided by the huge ‘highway’ created by the Danube River. If one is to believe the initial reports from scientists, it attracted its name because of its ferocious hunting qualities, eating just about everything in its path of a similar or slightly larger size, even young fish. It especially enjoys our indigenous species, the Gammarus ¬shrimp, which is so important in many of our rivers and lakes as the staple diet of trout, young salmon, grayling and many other species.

The question is, how did it leap the Channel and arrive in Grafham, and what do we do about it, now it’s here? The worst possible scenario is that it was pumped in from the Great Ouse, because that means that it is already distributed beyond the confines of a stillwater. If so, eradication is almost impossible, and we might have to accept that our invertebrate populations will never be the same in those ecosystems that it infests. However, there might be the chance that someone emptied the contents of their aquarium into Grafham and, with little spillway, it might just be contained within the reservoir. If this is the case, then simple biosecurity measures – ensuring tackle and equipment, especially felt soled boots, are thoroughly dried out between fishing trips - might just stop the spread. However, don’t hold your breath, and I have a nasty feeling that our killer shrimp is about to join the growing list of alien species such as knotweed, balsam, signal crayfish, mitten crabs etc that are blighting our aquatic environment.

Having said that, I think the fact that anglers were the first to find this shrimp is, potentially at least, a huge boost to our environmental credentials. David Bellamy once famously called fishermen the eyes and ears of the waterside (he actually said riverbank, but same difference), and this is a perfect example. If the angler in question had not been fishing the bank at Grafham (having had a terrible time with the weather the day before in a boat on Rutland) and seen fish going mad feeding on the shrimp, the species would almost certainly be undetected now, the survivors insidiously feeding their way through water boatmen, damsel nymphs and the like.

So, how to build on this piece of angler observation? Well, it really does give an immediate and easily understood example to David’s words, and is a robust rebuff to those that say – and, more importantly, will say in future – that anglers are merely cold hearted killers with no more interest in the environment than the next fish they can hit over the head. S&TA’s own strapline – Game anglers for fish, people and the environment – was not just written as a trite one-liner. We genuinely believe that if it wasn’t for our interest in aquatic life, and the massive investment we make into managing and conserving our rivers, stillwaters and the myriad species which depend upon them for their existence, then our waterways would be in a much poorer state than they are at the moment. And let’s not kid ourselves that they are in any great shape – the Environment Agency may state that 70% of rivers are chemically clean, but they have to admit that only 26% are at good ecological status at the moment - the only standard that really counts - and expect this to rise by merely 5% by 2015.

The Riverfly Partnership has been so successful since its inception in 2007, with over 650 volunteers, mostly with angling backgrounds, regularly monitoring their local rivers for invertebrates, working to trigger levels that, if numbers drop below, the EA can be called in to take remedial action. This is the type of community involvement that the new Government is looking for under its ‘Big Society’ banner, and is an intricate part of Water Framework Directive delivery. Anglers actually doing something individually that could make a substantial difference to the health of their rivers by picking up pollution incidents and just generally monitoring the health, or otherwise, of the water environment. That is a contribution to conservation that trumps many a do-gooding wordsmith, and will be a powerful card up our collective sleeve when the antis have another go at angling, as they surely will do sooner or later.

So, the killer shrimp might be a confounded headache for water managers and scientists over the coming months and years, but the silver lining might be even more significant. I am about to meet the new Fisheries Minister, Richard Benyon, for a talk about the future of fisheries management in England and Wales, and you can be sure that I will slip killer shrimps and eagle eyed fishermen into the conversation somewhere. But then, the Minister is a fisherman himself, so he knows our worth already, and that gives a great advantage upon which, on your behalf, we intend to build.

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