I was out fishing Farmoor 2 on Sunday in the boat, and found the fish eager to get hold of my boobies

.
Betweeen the three of us we had a good spread of fish between 2 and 4lbs. Some were recently stocked and were short, plump and had slightly rounded tail fins. Others were long, skinny and silvery.
The fish that I took home and filleted had either the usual fat around the stomach, or completly nothing and just a really fine stomach / intestine tract that was completly empty and had no fat.
What I am worried about, is that with the obvious lack of natural food about at this time of year, will a lot of the less recently stocked fish die of starvation while waiting for an abundance of food to appear in the spring? The fry may be too large now, there was no daphnia or shrimp around and the only thing I could see in one stomach was a bloodworm and a couple of fag butts...
I know that there metabolism slows down and that they have made it over the worst of the winter, but what are the odds for fish survival over the winter in large resevoirs?