"One way to get that size forage , assuming you can stock tilapia there, is grow them in the forage pond. Using aquaculture methods (lot of work and feeding) you can grow 3000 lbs of tilapia in the 1/2 acre and gradually sort and move them to the big pond."
Why is it important to sort the tilapia before moving them to the main pond? (That seems like a significant amount of work.)
To be sure it is extra handling and stress on the fish ... but maybe not as much as you are imagining. Fish are typically sorted by screening. So this involves a device with bars equally spaced that will allow fish of range of lengths to swim through. The fish seek freedom through the screen and a combination of (two of them) will retain fish of a given range of lengths.
Or is your tilapia brood stock just too valuable to remove from the forage pond?
age 1 Brooders are valuable and if the forage pond is to produce TP forage through out the summer then it is preferable to retain them. One of the more ingenious methods I've seen is to produce fry in two or more fry ponds from the same brooders. This involves allowing a spawning sequence of 21 to 30 days and then removal of brooders by large mesh seine to go into a recently harvested and refilled fry pond. The brooders will go back into the original pond after completing a brooding cycle that finishes about the time the original fry pond is harvested. On a two pond system, the fry are harvest every 40 to 60 days. This is a less labor intensive way to get high volume without artificial spawning. With artificial spawning, seed harvest can take place more rapidly at cycles between 10 to 14 days. In the tropics, these systems will produce fry year all long that are measured in many tons per hectare even though they are not optimally managed.
I would mention that my angle on this for the OP wasn't from the production of ideal forage. Whereas, Eric's description is a good example of how to optimally do just that. I saw the relative size of the forage pond (as related to the main bow) as a significant challenge. The proportion of the forage pond is only about 4/10 of one percent that of the main bow. I considered this to be well below an optimum proportion for a forage pond (Eric what are your thoughts on ideal proportion for BG and for TP respectively?). I would rather prefer to start with less brood and grow the fry to full maturity so that they can begin producing fry upon release to the main pond. In such case they are optimal prey for large bass AND are producing young. But there was so much space in the main bow ... I thought it may behoove the original poster to grow a much greater number of fry to a stage where the weight of females can be maximized (as proportion of production) upon release to the main BOW. By waiting to full maturity (~4" for females ~5" for males) only 1/3 of the harvest weight can be female. It may still be better to delay harvest until then but the scenario I presented allows many more individual females to be stocked on the first crop of TP. Proportionately, the weight at day 120 is 3 times that day 70 if equally distributed between the sexes. This corresponds with a 67% reduction in the number of individuals that can be grown. Immediately, however, it is obvious that survival to breeding age must exceed 33% in the original proposal in order exceed the alternative of growing a smaller number to full maturity (in retrospect, the alternative of growing to full maturity carry's less risk). In the end, I considered the forage pond of little influence for such large main bow unless the forage pond was able to produce
brood fish that could make a more profound influence by reproduction. After further consideration, I do think it is better harvest the forage near sexual maturity to ensure the effect.
