Invert monitoring

I was lucky enough to attend an invertebrate monitoring workshop which was run by Stuart Crofts at Gibson Mill in Hebden Bridge.

We met at Hebden train station and got driven up in groups to the location, the weather was looking good, the sun was out but it was on the chilly side and rain was forecast later on in the day.

When everyone had arrived we got briefed on what the day would consist of and what we would be doing. I’ve never done anything like this before so everything was new to me. Just looking at pictures of the creatures that lay on the bottom of our rivers fascinated me.

after we had learnt about the invertebrates we were looking for it was time to go outside. everyone put on their willies and there I was stood in my waders, wading boots and jacket. I was not getting cold and wet!! we headed up-stream where we found a suitable place where it was safe to enter and exit the river safely.

to do a kick test you will need a pond/hand net, an empty bucket and a stop watch.

to collect invertebrates from the river you have to do a three-minute kick sample using a pond or hand net. it is done by standing in the river with the net held out in front of you on the bottom of the river. you need to position the net so that the flow of the river opens up the net. You then use you’re feet to disturb the river bed which will release the invertebrates and the current will carry them into you’re net. when you feel you have collected a good sample, your partner will pause the stop watch while you empty the contents of your net into the bucket. after you have finished your kick sample you need to wash it. this helps when it comes to sorting your sample. to do this you’re partner needs to hold the net whilst you pour the contents of your bucket into the net, leaving behind the unwanted stones and gravel in the bottom of your bucket. repeat this process until you think you have got most of the invertebrates out, but to be safe check through the contents of the bucket on the bottom of stones for the ones that like to hold on, especially cased caddis. when you are happy with what you have empty the bucket back into the river and re-fill the bucket with water from the river and empty the net into the bucket.

just as we were about to finish the field work it started to chuck it down, hail, sleet and rain! luckily we had a room so we could do the rest inside. some buckets had more than others but every one was happy with what they had. Stuart set up the microscopes so we could have a closer look a what we caught. we were looking for 8 species in total they came under 4 categories.

Caddisfly larvae cased caddis and ceaseless caddis
Up-wing fly larvae – may fly/blue winged olive/flat bodied Heptageniidae and olive baetidae (all have 3 tails)
Stonefly Larvae – stonefly (all have 2 tails)
Freshwater Shrimp – gammarus


the best part of the day for me was defiantly sorting the different invertebrates into the different species, that involved using pippet, plastic spoons and brushes. once you have sorted the sample you then have to count it, by counting that usually means an estimate. in one container you may have 6 of one group which would be easy to count. on the other hand you could have more than 100 in another group which would make counting them near to impossible. so what we did was we used an estimate key.

1-9 was in category A
10-99 was in category B
100-999 was in category C
over 1000 was in category D

we then put our recordings into a table and compared them with everyone elses.


when we had all finished sorting out the samples we had the chance to go and look at everyone elses. we even got to see some hatch. it was amazing to actually see what is living in our rivers but also it helped a lot with my fly tying as to how to imitate them.

every one who took part in the workshop had a lovely time and it was nice to meet new people. although there were only a hand full of anglers in the room there were many people there who were interested in the wildlife that lives in our rivers. one couple who were there are in the process of creating a wild life conservation park!

I cant wait to do more sampling in the future!

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