Flies tell no Lies

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Did you know that ‘flies’ are the most accurate indicator of how well our streams, lakes and rivers are doing ?

The Clinger Mayfly Nymph got its name because it uses the pressure of the flowing water on its head to ‘cling’ to the rocks. The presence of this fly in a river is a sign of the finest water quality possible ! Insects exist all over the world and survive in some of the harshest environments on our planet. It is believed that they outnumber all other animal species combined ! 


One of the worlds top entomologists (insect specialist) tells us that with enough knowledge of flies it is possible to analyse every possible input, pollutant and stressor to our waterways. And what is astounding is that there would be clues to all of these, not just at that moment, but their levels over every second of the past year or more. This is extraordinary. As part of the preparation for the journey of the “deoch na Laoi” our “pure drop” of the river Lee in Cork, we are initiating through this site a River Lee Fly Recording Unit. 


We will document and record these tiny, age old inhabitants of our river to see what their story is. Apparently there are only one million insects that have been identified and somewhere between 5 and 8 million remain unknown to us ! Are there unique flies on the lovely Lee that don’t have a name yet ? We would like to find out and we would love you to help us.  We will post more information as this develops here and on our Twitter , FB and Instagram platforms.


Riverflies, along with other freshwater invertebrates, are at the heart of the freshwater ecosystem and are a vital link in the aquatic food chain. Riverfly populations are affected by many factors, predominantly water quality, habitat diversity, water level and flow rate.  Their common characteristics of limited mobility, relatively long life cycle, presence throughout the year and specific tolerances to changes in environmental conditions make them powerful biological indicators to monitor water quality, and are commonly referred to as ‘the canary of our rivers.’ 


WANTED : The Source To Sea Team are on the lookout for a Riverfly Specialist to help us build a Fly Profile for The River Lee.  

The job description is as follows :


Age : 7- 9 yrs old. Girl or Boy .

Salary : None ! but lots of perks!

Academic Qualifications :  None , just a fascination for insects will do.

All those interested please contact us directly through our website. 

All activities will be in public spaces, in the presence of two trained and Garda vetted adults. The findings and research will be filmed for publication on our site. You cannot be camera shy for this post. This is the most important part of the Source To Sea idea.