https://www.msn.com/en-gb/news/uknews/how-the-return-of-beavers-is-benefitting-brown-trout-in-scottish-rivers/ar-AAPqFiI?ocid=msedgntp
Certainly if you read any north American books and articles the best trout are often found in beaver ponds. The great John Gierach forever sings their praise although very old beaver ponds appear to be less productive. A bit like when new reservoirs / hydro dams are built an initial food bonanza followed by a sharp tapering off. There is lots of empirical evidence for this.