Illinois Longhorn,
If the ones around here tasted anything but horrible, my neighbors would have eaten them long ago.
BarO,
I hear you, in the beginning when all of the fish were "my babies" I went after them pretty hard. I bought a bb gun,strung up wire along the shore, put heavy bamboo cover near the water line and threw rocks until my arm gave out. If nothing else they are persistent. They found high or low spots in the wire, they came early, they came late, they started at the far end of the pond and finally they used my foliage for cover.
Finally I gave in, they beat me. I decided that in a pond my size the tilapia could serve us both. You, however, have LMB which hunt in the same zone as the heron, while only my small fish venture that close to shore. I wish I had an answer for you.