The mayfly and the Angler’s Monitoring Initiative

© John Slader Mayfly Commended Riverfly Partnership / National Insect Week 2010

Last week’s mayfly special was so popular that we couldn’t publish all the submitted articles.  So here, as an excellent, hopeful penultimate post, Louis Kitchen from the Riverfly partnership discusses the role of the Angler’s Monitoring Initiative in British mayfly conservation

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A big hatch of mayflies must rank among the most enthralling wildlife spectacles that the UK has to offer – especially to those who operate in and around the river. Birds, bats, fish and fishermen are among those who appreciate the mayfly. And among these it is surely not just the fisherman who has felt the effects of a decline in the frequency and scale of hatches.

Many factors can affect populations of mayflies and other freshwater invertebrates. Intensive agriculture and industry has resulted in a large number of our watercourses being modified, and this is certainly among the causes of a decline in our more sensitive species. Occasional pollution incidents can also have devastating effects on invertebrate populations, which may then take a long time to recover – in heavily impacted rivers a full recovery may never happen. Most people associate pollution incidents in rivers with dead fish, but by the time pollution has become severe enough to kill fish, a lot of invertebrates will have been wiped out.

It is this sensitivity to pollution that makes invertebrates incredibly useful for monitoring our rivers. By looking at some of the most sensitive invertebrate groups, anglers and other stakeholder groups are keeping tabs on water quality in their local areas through the Angler’s Monitoring Initiative (AMI). The focus is on the riverflies – stoneflies, caddisflies and mayflies – and the principle is quite simple: If a monitor takes a sample at a site one month, and finds healthy populations of riverflies, then returns the next month and most of them appear to have vanished, then it is likely that there has been a problem at some point in the intervening month.

The AMI was officially launched by The Riverfly Partnership in 2007, and there are now over 50 groups involved, with around 500 volunteers monitoring sites across the UK. Groups work closely with the local statutory bodies – the Environment Agency, Scottish Environment Protection Agency and Northern Ireland Environment Agency. If a decline in riverfly populations is detected then the statutory bodies are contacted and will be able to assess and deal with the problem. By monitoring every month the volunteers pick up on declines in water quality that may otherwise have gone unnoticed, and ensure early action to prevent problems escalating. In some instances severe pollution incidents have been picked up on; there have been three prosecutions of polluters, resulting in fines for the companies involved, that have come about because of AMI monitoring.

It is important for the future of British rivers that communities take an interest in their well-being. By empowering local people to look after the water quality in their rivers, we allow rivers affected by pollution to improve naturally without suffering further setbacks. In this way we may see the return of huge swarms of mayflies swirling above the water – good news for everyone, especially the birds, bats, fish and fishermen.