Fish eat, breathe, and poop. There is a limit to how many pounds of fish a given bow can support, so the decision has to be made as to what species and how many the pond can handle. It's not nearly as simple as just dumping in fish.
Tony, while I have no doubt there is an upper limit to how many ponds of tilapia can be too much, but 100's of trophy bass ponds get stocked annually with as many as 200# per acre of brood stock.
As for the comment of "Tilapia doing as good a job as grass carp", tilapia and white amur do not prefer eating many of the same foods...grass carp will starve eating filamentous algae, where tilapia thrive on as their favorite food.
When it comes to tilapia dying in cooler areas and "if you want to stock them each spring"...Like anything ponds, we do things based on our goals. If a person does not want chemical control of many plants and algae, does not want to or can't regularly feed expensive, high quality food, wants overall water quality improvements, and all at the lowest possible price and no manual labor other than writing a check, stocking tilapia where legal is a total no brainer.
