The Environment Agency (EA) in Hampshire and Salmon & Trout Conservation UK (S&TC UK) have for the first time agreed key environmental local bespoke targets for the Rivers Test and Itchen to help drive ecological improvements. S&TC UK believe this is a precedent for other rivers to follow.
The local bespoke targets are set around the number of key water invertebrates - that should be expected in a 3-minute kick-sweep sample in these 'Classic' chalkstreams.
The targets are for the rivers to support at least 10 separate mayfly species and 500 freshwater shrimps known as Gammarus, in the middle and lower reaches of the catchment - all of which are susceptible to different forms of pollution and so their presence or absence gives an accurate analysis of the environmental health of a river. Targets for the upper reaches are still being developed.
These local bespoke targets, supported by independent evidence and the EA's own data, are one major result to come from S&TC UK's Riverfly Census research, carried out by Dr Nick Everall of Aquascience Ltd across more than 20 rivers in England and Wales.
River flies play a vital role in a river's food chain - lose them, and other aquatic wildlife will follow. Water invertebrates matter for fish, mammals and birds.
S&TC UK is fighting to stop a downward trend in the water life of our chalkstreams. Its national Riverfly Census data has showed that fine sediments and excessive phosphate nutrient are especially damaging to mayfly species, and while Gammarus are also susceptible, they are particularly sensitive to a whole host of other contaminants.
The EA routinely monitor chemical water quality and river ecology as indicators of river health. These new local bespoke mayfly and Gammarus targets will now feature in the way the Environment Agency monitors the health of the Test and Itchen.
Nick Measham, S&TCUK's Freshwater Campaign's Officer, said: "S&TC UK will seek to establish similar targets for the other 18 rivers currently in the Riverfly Census by working to agree bespoke river targets with the relevant local EA scientists."
S&TC UK's Head of Science, Dr Janina Gray, said: "While our recent analysis painted a generally worrying picture on the health of mayfly and Gammarus populations, we have now identified and agreed a simple scientifically credible benchmarking figure for invertebrates in a healthy river.
"Once we have a standard for all rivers along the lines of the local bespoke Test and Itchen agreement, we can help local river managers to develop solutions and so restore our waterways to their former glory."