Seems like the suckers are coming in from some other BOW. Perhaps they are migrating up the "Ferry Drain". If that is the case, I would bet fish will migrate up the "Ferry Drain" again and repopulate the lake now that the fish kill has been done. It may be a moot point trying to control the exact species that are going to be in your lake, with their being a way for "trash" fish to get back into the lake on their own again???