That article seems fishy to me. How a 19" trout managed to find nearly 20 shrews which are solitary creatures? It's interestingly that a fish biologist claimed that shrews are poor swimmers which isn't true. All shrew species were excellent swimmers and some species are aquatic or semi-aquatic.
I have heard stories of big Brook Trout eating Snakes, rodents, and even human garbage such as cigarette butts. And large Brown Trout become highly cannibalistic as large individuals... Trout dont just eat flies. They are pretty well-built predators.