It's been interesting to observe over the decades, even if I don't get up there (Emigrant) nearly as often as I did when I lived closer. I have definitely noticed that lakes I once fished now frequently have no fish whatever. Same in Desolation.

The only lake I've seen with active fish eradication (netting across inlets and the outlet, F&G interns camped for the summer) was Helen, near Tower Peak. I suspect, but don't know for sure, that backcountry planting is nearly gone or at least greatly reduced, and that has a greater impact than targeted eradication. As it turns out, many, many former trout lakes can't sustain fish populations. Years of drought are also hammering what once were year-round streams.

Contra all that, I've seen more Sierra osprey in the last five years than in all my other hiking years, combined.