I'd be highly suspicious that the cats are going to town on the trout. I grew up fishing 100-200 acre lakes in AZ that were stocked with trout in the winter-using trout in the 9-12" range for bait, Nov thru April. We'd catch cats all winter, even with water temps in the upper 30's, on trout. Cats wouldn't touch anything else until April or May. A 9 or 10lb cat can take a 12" trout without much difficult, IMHO.
Currently, I put in 200# of trout into my 2acre pond each November for LMB and bluecat food....I've never seen a floater in May or June, and I'm sure it's because they've all been munched by the cats, and bass to a lesser extent.
