In another thread, jpsdad provided a good answer to this question of fall harvest of fish. Reread his post.
https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=576491#Post576491His points were:
1. If the summer's fish weight gain is harvested at the end of the growing season, this thins the herd of consumers to allow all remaining fish sufficient available foods during winter to eat more and maybe grow or stay at good maintenance weight (if they are below the standing weight that natural fertility can maintain). They will not go hungry and they will likely gain a little over winter. Note the Fall harvest needs to remove enough fish to get the pond's carrying capacity or standing weight below what the natural foods will support.
2. Fall harvest also then allows more winter foods to be available for adult fish to eat more, be healthier and be in better body condition and ready for the spring time spawning season.
3. When fish standing weight is below what natural foods the pond can support fish grow well or best. Adding pellet food increases the pond’s natural foods and this suppliment feeding allows more fish pounds that the pond can produce. Adding pellet food increases the pond’s carrying capacity. However there should be annual harvest of the fish crop to keep the pond water a good healthy quality. Boosting the carrying capacity increases the danger of a fish kill. Be warned.
