Notes on Freshwater Biology

Freshwater such as lakes and rivers have determined the location of habitation through out history. Witness all the great cities: Rome and Cairo to name but two are built on rivers: The Tiber and the Nile.
The reason was the in history freshwater was important for drinking water, food, transport and a disposal route for waste. The fish obtained from the rivers was an important source of protein for the peoples living nearby.
Now in the 21st century freshwater fishing and other recreational uses of water such as sailing and narrowboat holidays are economically important.
The downside of…