Sunil - the abundance of GSH strongly suggests that the number of 13"-16" predators are lacking. Since you say the pond has LMB and HSB, each CC takes the place of one of the other shiner eating predators. Focus on removing the CC so the other predator species will fill the pond's predator carrying capacity. This should help noticeably reduce the adult shiners. Two other items for this topic. 1, focus on catching the shiners with small hooks as you sit and sip a Corona or give a bounty to neighbor kids who catch shiners and put shiners in a live box for you. Feed those shiners to the predators to condition them to eating shiners. Get more of this info technique from your buddy Condello who is an expert at this method. 2. It is easily possible that you don't have as many medium predators as you think are in the pond, thus there is less predation pressure on the various year classes of larger shiners.