The problem with guessing on numbers is the incredible variance in BG reproductive output. The variance is huge from a few thousand to 50,000 eggs per female. For example, to get 150000 thousand fry per acre it could take as few as 3-4 female BG or as many as 100+-. In addition there are other large variables like mortality. If one is that worried about BG numbers then grow them out to 4-5 inches in the growout pond and seine and place only the number you want at that size.

Experience will tell you what works over time. The easy way is to put about 50 good quality feed trained adult BG in the pond and let them go after it. Those 50 are not going to put a dent in BG fry numbers if they are fed. Growout the spawn for 3 months +- on feed, and let them all go in the big lake. Do habituate them in the big lake as mentioned earlier. See what the population looks like before the next years spawn and adjust from there.