TEXAS715 a very good question. Lets start with these 2 from the archives on carrying capacity (standing crop) and what effects it. The simplest way to explain it is being like an engine. Which it is after all. The closer you are to running it flat out the more likely you are to have a problem. The closer to carrying capacity the less room for error (including weather). In the south studies show that a pond will move toward its natural biological capacity (not including feeding and fertilizer which can increase capacity) in 2 to 3 years. After that , absent some productivity increase (Feed and/or Fert.) , you are dealing with managing how that amount is divided between the existing fish (balanced , LMB crowded , forage crowded , etc). There has to be room for some fish to grow bigger mostly by eating (eliminating other fish) for them to spawn and to go through the normal life cycle. Feeding and fert. work the same way just at higher levels over the same period. Whether you are feeding fish pellets or lots of forage you are still feeding fish as per Bob's comment below.

Good list of carrying capacity factors with discussion.
http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=22;t=000004

Bob's comment "
10) Feeding fish can be a great asset, by expediting growth rates and increasing a pond's standing crop. But, be aware of this...feed two pounds of fish food, you get one pound of fish, one pound of waste. Your pond becomes a septic tank. Too much waste in too little water leads to a natural correction. And, you won't like it.
From http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=22;t=000013

On the other point - studies show that if there are so many BG (probably other fish as well) that the LMB are overwhelmed then LMB will not attempt to spawn. This can be the start of a cycle with bad results. No new LMB - to many BG - no LMB spawn - more BG of smaller size and on until every thing in the pond is stunted and out of balance. That situation is not common though.

Not sure I answered your question but it is a start.