Hi,
I was fishing there last year as it was close to my house. The permit was £15 for the year or £5 for the day so I got the years brown trout permit. This stretch was run by mid Clyde angling society.
There were the same folk there anytime I was down and I never saw anything bad around the area. Most people were spinning but when salmon were going up river there were a few people out fly-fishing. I always went with the fly rod last year.
I was always between the castle and the Blantyre bridge. You cant fish between the Blantyre bridge and Blantyre weir and you cant fish 50m (maybe 100m) up from the weir towards Strathclyde park. You can go as far as Bothwell bridge and their stretch of river starts somewhere at Dalmarnock.
I wouldn’t go down if the water at Daldowie is above 80cm as it is too fast, strong and high in my opinion.
I was catching brown trout with a rough size of 8-9inches every time I went down. I am sure there are bigger ones but I never got any. My favourite spot was between the castle and the bridge, on google maps it looks like there are rapids at the point. When the river was less than 80cm at Daldowie I was at waist height and I am roughly 5ft 6inches. There is a spot here for bank fishing and I saw people spinning here a lot. I even saw (a guess but it was massive) a salmon swim past me when at this spot but I couldn’t grab it in time

(by the way thats a joke )
Further up towards Blantyre bridge is good but it is always crowded.