James,
Yup, ... I fish almost exclusively on an Atlantic Salmon river:
http://pages.videotron.com/fcch/homewaters/RvSteMarguerite.html
We have Salmo salar and sea run brook trout.
Adult Anadromous brooks act exactly like their Salmo cousins. They don't come into the fresh water to eat, they come here 'cause there are prime spawning beds. In fact, the river here is relatively POOR in terms of feeding habitat. No real hatches, very little aquatic micro faune.
An adult sea run brooky will come into the river in mid summer (between mid June 'til late July, though most have arrived in the second week of July).
Once there, they will lurk about in shelter lies, deep pools, slow current. As the current is not strong in the holding pools, they will usually school up and you can have litterally dozens and dozens of lunkers holding off a shelf, in the lip or tailouts. They'll often be holding near the salmon as the beds are in similar stretches of the river. They hold upstream or downstream of beds.
Not eating in fresh water, a nice 6lb hen will lose over 50% of her weight over the summer. Though they don't eat, they seem to be more curious than the salmon and will inspect flies, sometimes moving 10-20 ft to come see a new offering only to slide back to their station.
They do exhibit SOME feeding behaviour and come out on occasion into seams and "normal" prime lies taking dead drifting anythings.
Brookies have a reputation for "dumb" behaviour and taking any fly, ... Not always true. (ask my girlfriend):
http://pages.videotron.com/fcch/why_we_fish_ii.htm
Sea run brookies here (and not in all rivers) have their equivelant to Grisles too. In late August, the juveniles come into the fresh water too. Apparently, the fjord is too cold in winter (water often BELOW freezing). These critters come in in schools of hundreds (and in '98 ... thousands). They EAT taking anything that is offered (depending on the conditions).
Sound fun ??