River Fly Sampling on the Wharfe and Skirfare
- Tim Scott
- Nov 19
- 2 min read
Updated: Nov 20
For the ARMI (Anglers River Fly Monitoring Initiative)
Background
The aim of the scheme is to continually monitor the health of the river through the monitoring/counting of eight key sentinel insect species living in the river. Many of these species eventually emerge from the river as flies. The number and type of insect species is counted (scored). The total score is used to assess the heath of the river. For each sampling site the Environment Agency (EA) allocates a “trigger level” (minimum score). If this minimum score is breached then further investigation/action by them is actioned.
Around three years ago I decided to train as a river fly monitor. Primarily this would, I thought, help me with my fly tying by giving me be a better understanding of what the insect life below the water level ie trout food looked like. Sadly it was only the latter that improved.
We have been allocated three sampling sites on the Rivers, two on the Wharfe and one on the Skirfare. Each of these sites are sampled once a month during the fishing season (weather and river levels permitting). The process involves wading into the river and “kicking” the riverbed to disturb the insect life which is carried by the current into a sampling net. This process has to be carried out for a three minute period. The net is then emptied into a tray to allow the contents to be assessed and the insects counted.
I have been greatly assisted with the above by my wife Jane who has developed a real fascination with the insect life we have found and has a far better memory.
Over the last three years of sampling we have never breached a trigger level and the Environment Agency have increased the levels following our positive results. We have also changed the location of one site as it was difficult to access when the river was high. Our current sampling sites are:
Below Skirfare Bridge on the Skirfare
Above Conistone Bridge on the Wharfe
White Beck (above the wooden pedestrian bridge)
There are eight sentinel insect (invertebrate) species that we monitor and count. These are:
Please Note: The above images are not to scale, ie the olives are much smaller than the stoneflies etc.
Results
I hope these tables and graphs are readable at this resolution as there is quite a bit of information to display.
We will update these files as we get more results. This will probably be early in the new year now as the river levels are usually too high and it's very cold.
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