As for me & set lines, I got to where I set out lines just before T-Day. The Blues would go on up from smaller, and from 20 to 40 pound range on Lake Limestone. Probably slacking down by first to mid March. February is considered Big Blue month. I basically use perch & goldfish.
The bigger ones hit all the time. But it seems to be more plentiful in cooler weather. Probably the reason is that many fish for them shallow or deep, and they may be suspending at mid-level due to the thermocline during the time it is active.
I prize the 12 to 14# Blues the most, as to cutting boneless steaks from the backstrap. They look like the shape of a " B " or " 8 " & deep fry them. Simply the Best! However, it seems some of the lakes here & there have those in the slot that you cannot keep.