Around here, the first thing I would ask would be is: has anything happened to the predator fish population? Tons of little gills might indicate a big population of stunted fish. If not, then now, coming toward late ice, I would start moving into staging areas just off spawning shallow flats. I've been catching bigger fish in 3-5 FOW near inflows of snowmelt, and especially around green "moss" (filamentous algae) beds.