Just an update to this thread.

A LOT of water has metaphorically (and physically) flowed over the dam since I started this thread and my journey with the GSF therein. If you look on page 1 it was a little over six years ago I started learning about GSF and managing around them.

I can say now that I hardly ever catch one now when we fish this pond. The LMB have cleaned them mostly out and the BG have out spawned them.

Once I introduced LMB large enough to eat them and BG large enough to spawn and not get eaten by the GSF, it became just a matter of a couple of years till they were no longer an issue.

So my analysis is if you are willing to work with them and have the time you are willing to wait (in my case a couple years to turn the pond around), they can be managed around. If you are in a hurry, killing off the pond and starting over is probably a quicker solution.

The key to my success was having available advanced size LMB and BG to stock the pond with. If I had put in just normal size fingerlings the GSF would have just had them for lunch. Fortunately I had another pond where I could easily catch and transfer larger size stocking fish to this old refurbished pond.