River Fly Surveys

The Cressbrook & Litton Flyfishers’ Adult Upwing and Stonefly Records 2016


This is the second year of this project and it has once again produced some interesting results. The way the project works is quite simple. In each of the three fishing huts there are “sample packs” available for members to pick up. Each sample pack consists of a small zip-lock bag inside of which is a screw top sample tube and an information slip. Members are invited to take along a sample pack when they go fishing and if they come across any upwing flies, or stoneflies, they can be caught and put into the sample tube. On returning to the fishing huts the sample tube is filled with some preserving alcohol and, very importantly, the information slip is completed with the members name along with the date and the beat number where the sample was caught. The tube and the information slip are then put back in the zip-lock bag and placed in a box where I can pick them up for analysis.

The term “upwing flies” relates to the insects in the order Ephemeroptera, this includes some very familiar insects as far as the anglers are concerned such as the blue winged olives, mayflies and iron blues. The name “stoneflies” relates to the insects in the order Plecoptera, these are less well known and like caddisflies (that I also study in detail) tend to be overlooked by the anglers yet they are often taken eagerly by the fish the anglers are trying to catch.

I only require the adult stages of these insects for this project (obviously for the flight period data). And, as anglers will are aware, the upwings are peculiar in that all our UK species have two adult stages. Anglers know these as duns and spinners. It does not matter which are collected, in fact getting samples of both is very useful as some species are easier for me to identify (to the full species level) as duns while others can only be positively identified at the spinner stage.

Around ten of the club members collected samples over the fishing season along with both of the river keepers and Steve Yeomans (Fishing Guide). I also collected samples while walking by the river or doing other survey work on the fishery. As a result of all these efforts I had to check around 300 specimens. I have summarised the results for both the upwings and stoneflies on the pages following. Additionally, you will find in the appendices at the end of the report all the detailed records of what was found. Lastly, I hope you find the report interesting as it once again highlights the richness of this wonderful river which I hope no one ever just takes for granted because it is a very special place.

Stuart M Crofts, January 2017

Click here to download the full report.