Hosmer Lake is an interesting one, Steve guided there earlier this week and I guided there the last 2 days. It seems to me there has been a winter kill, or heavy predation of the fish. I’d estimate the fish population to be at least half missing. For example, where we’d see 100’s of fish in the channel scooting away from the boat, I saw less than 10 per trip. There was evidence of higher weed growth, especially arrow leaf with the stems that grow to the surface and have the reddish leaves on the surface most of the summer and fall, and the dense carpet of underwater weed growth consisting of what I am guessing is 2 or 3 species of aquatic vegetation. If that was growing heavily before it finally iced over, we might have lost oxygen in some areas of the lake under the ice. This happened at Lava Lake 2 winters ago and we saw a tremendous fish die off. What happened at Hosmer is not at that scale as there are certainly nice, well conditioned and healthy fish still around, but not as many as I am used to seeing and Steve agreed in that assessment totally. 
The last couple of days we did see some callibaetis hatches with a lot of black spinners about. My BBR Callibeatis did the trick both days. Also, my Jig Style Cates Turkey under an indicator worked both days. Leeches have game for sure. We saw fish rising to Midges yesterday morning but they got spooked by the boat and a cormorant chasing through the area where they were rising. 
There seems to be a number of cormorants on the lake now. I’m told they can eat trout up to 4 pounds. Yikes. I’ve not really seen cormorants on Hosmer before. Have you?
Otters too. Who’ve always been there, but I know are doing a number to the trout population now. 
I see ODFW has 750 trout slated for a Hosmer re-stocking about July 11th. But if what I am seeing holds true and all of those trout are not hidden away in a dark corner of the lake, that means it may be a lean year at Hosmer compared to years past.