Here is one point to consider before I take a WAG later on your blue text question.

In southern ponds a normal new pond will reach carrying capicity (max natural standing crop), meaning no feeding or fertilization but as is, in 2 yrs or less (18 mths is used also). From that point on you are managing the factors noted above in an effort to get the quality/type of fish population (#s and sizes). The amount in poundage remains about the same just the makeup of the population changes. Maybe Bill can provide the amout of time needed to reach carrying capacity up north. I bet it is about the same time but have not seen that info in studies.

Why do I provide this info ? You have fish in the pond now. Even though it is bigger now those fish will fill up the carrying capacity fast.