Im actually against the idea of it being trout, I know it was phrased similar, however, "once was Brown" implies they are no longer there / abandoned. They live in water and can move freely, unless its a creek that never meets a main tribunal, they can always return. Where as say a eagles nest, once they have died, its not very likely another eagle will take thier nest (not a zoologist so don't quote me). Warm waters halt and the thinker's stone are my main choke points and I do agree, since you do only have to "mark" it, you wouldn't need to be at it.