O2? What does a mobile phone service have to do with performance fly fishing, I here you say. Nothing! I just used the chemical symbol for oxygen (it’s an affliction that goes back to my previous life).
Anyway, non of us would last long without oxygen and it’s the same for fish too. High summer means higher water temperatures and lower oxygen levels in the water. This impacts lakes far more than rivers overall and if you want to find trout willing to feed, locating areas of cool water is vital. Natural springs are a favourite hangout for trout, checkout the video below.
When you see concentrations of fish like this, you can understand that 10% of the water maybe holding 90% of the trout. If that sounds unrealistic, remember, eating is not a priority if you are unable to breath!