Willi wrote in message ...

Higher water temps are generally the limiting factor in where trout can
survive. As a river flows downstream, average temps generally rise until
they reach the point where the trout can't survive.

Willi, have you ever explored downstream to see if trout move down at
different seasons? I could imagine that trout move down in winter (if
there's enough water) and maybe back again when it gets too warm. You've
talked here before about daily migrations of a hundred yards, but are
there seasonal migrations on the order of miles?

I could also imagine that in high-runoff years, quite a few trout may
find themselves (either "purposefully" in their pea-brains or accidentally)
quite a ways downstream, and not really make an effort to move back up
as the water warms. This could be an opportunity to harvest some decent
trout that would otherwise perish anyways. Maybe in the few weeks after
runoff and before the water really starts warming up.

Jon.

I guess it should be noted that you live near streams that make a
fairly abrupt change from good trout water to uninhabitable, with
a fairly short amount of "marginal" habitat. In other areas of the
country, this situation may be uncommon (I'm guessing).