Do you have any other predators in your BOW? I had GSF come in with the water when the pond filled. I culled out 350 of the smaller ones to a friends pond to feed his LMB (surviving on their spawn). I've noticed a sharp decline in the smaller sizes especially this year after I introduced LMB, CC, and BC the summer of 2915. I know I have some big ones in the pond, I caught some 8"+ ones last spring. I have not hooked any big ones this year, but I know they've spawned. Unless you've got something in your pond big enough to eat the big ones, they should be fine. I'd just release them back into your BOW and keep feeding your forage base.
PM Sparkplug...he grows some monster GSF...
