I know this site is mainly concerned with the anadromous fishes but appeal to your knowledge of lakes for an answer to a curious scenario: recently I hiked in to Twin Lakes here on Orcas to try out my new float tube, and was surprised to find both of these little gems full of rough-skinned newts (Taricha granulosa)--the orange bellied variety. I thought at first that the big fish would be eating them, but a field guide I have mentions that "...this newt is so strong in the poison department that it can sicken or even kill a small animal that eats it."
They swam freely about, and I even saw a few couples engaged in amphibian reproductive affections. Saw many rises in the larger lake, and hooked a half dozen 6" brookies on an orange caddis. No sign of larger fish, though, or of larger rises.
Do fish eat these newts? Has anyone experienced success fishing lakes that were full of them? And what do they indicate about the health of the lakes?
I'm going to try the wooly bugger thing today--gotta find the ones that'll put a bend in my rod!