Friday, 2 October 2009


While walking around Mapperley Reservoir a couple of days ago, it was clear that the water level which I mentioned a few days back, had fallen even further and was now about 3ft lower than normal. The result of this is to reveal the muddy edges of the reservoir which are more usually submerged. Among the mud, we were surprised to see these creatures.
Known as Swan Mussels (Anodonta cygnea) they are a large, fresh-water bivalve mollusc. Found widely in fresh water around the country - although rarely in Scotland - they are not often seen.
At around 5" long, these seemed quite large, but they can reach as much as 8". We were astounded to see a couple of them moving very slowly amongst the mud, using a large and muscular foot to pull and push themselves along.
While searching for information about these animals, I stumbled upon a report by a certain W.T.W. Potts entitled "THE RATE OF URINE PRODUCTION OF ANODONTA CYGNEA". It makes you wonder what is missing in the lives of some people that they would want to dedicate their lives to such subjects! In case you were interested, it turns out to be about 237ml per day at a temperature of 17C. There, now you are fully informed and can rest easy.
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