River Fly Surveys

The Cressbrook & Litton Flyfishers’ Adult Upwing and Stonefly Records 2018

This is the fourth 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 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 fish the anglers are trying to

I only require the adult stages of these insects for this project (obviously for the flight period
data). And, as anglers will be 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.

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 rare and very special

Stuart M Crofts, March 2019

Download the PDF for the Cressbrook & Litton Flyfishers Club – Adult upwing and stonefly report for 2018