That's abysmal Bob.
There's a local wee burn near me in Prestwick, looking back at historical maps there's quite a few named fishing pools on there, but the water is milky like 80's bathwater. Absolutely no signs of any fish life, Ayrshire rivers trust only picked up the odd Gudgeon at their last survey.
Sepa not interested - 'it's natural eutrification' - is it buggery, it's farm and industry pollution, pure and simple.