Salmon & Trout Association 2015 National Riverfly Census

Tiny shrimp points to ecological malaise in England’s iconic rivers

The Salmon & Trout Association (S&TA) has launched its 2015 National Riverfly Census, a major independent scientific study on twelve of our iconic English rivers. Its prime aim is to discover the current status of important aquatic invertebrates that are key indicators of a river’s health.

The S&TA fears that the Environment Agency (EA)’s limited resources are not allowing sufficient monitoring to take place and, therefore, the true state of our rivers is not being accurately recorded. As a result, many rivers are not being properly protected.

Samples have been taken in each of 12 rivers across England, including all four chalkstreams which have Special Areas of Conservation (SACs) status, including the Hampshire Avon, Itchen, Lambourn and Wensum – together with three other SACs – Axe, Camel and Eden – as well as five nationally famous fishing rivers – the Coquet, Dove, Test, Ure and Welland.

S&TA’s Head of Science, Dr Janina Gray, explains, "The samples are being independently analysed by a professional entomologist down to species level. This can yield a very accurate ecological fingerprint at each site in terms of flow, sediment, nutrient enrichment and organic pollution, caused in the main by over-abstraction, poorly treated sewage, septic tanks and agricultural diffuse pollution. It can also highlight potential chemical contamination. These results will enable us to present our data to the EA and challenge them to be more robust in protecting the ecology of our rivers."

The most worrying element to emerge through the early results of the S&TA’s 2015 National Riverfly Census is the seemingly massive decline of the Gammarus shrimp on monitored rivers, including the once pristine Upper Itchen. Historically, the levels of this important invertebrate would be in the region of several thousand in a three-minute kick sample. However, sampling at four sites on the Itchen has revealed numbers between 50 and 185. Shrimps are the foundation of the aquatic food chain and very sensitive to chemical pollution. Basically, lose your shrimp and many other species may follow.

Paul Knight, Chief Executive of the S&TA says, "It is absolutely shocking that a highly prized and protected river like the Itchen has become so degraded. The Gammarus pulex (freshwater shrimp) and other aquatic insects are the lifeblood of the river. If they disappear then freshwater fish, otters, kingfishers and all those other species that depend on healthy river systems will also suffer.

Nick Measham, S&TA’s Freshwater Campaign’s Consultant, adds, "We suspect that development and economic growth are trumping environmental considerations, even on Special Areas of Conservation like the Upper Itchen. We hope our action, backed by sound scientific data, will prompt a positive response from the Environment Agency and that they will drive forward mitigation measures to prevent further potential disaster."

Paul Knight concludes, "We would like to work with the EA to increase protection for our rivers, fish stocks and aquatic life, and will make all our data freely available to them. However, we will no longer tolerate inaction and, if forced to, we will use all challenges open to us to ensure that the protection of our freshwater environment and dependent species receive the highest priority from those charged with their protection."

An interim report will be produced when all the spring results are received, and a further five samples for each river will be taken in the autumn before an annual report is published early in 2016.