From the paper: "With a broodfish
stocking rate of 100 pairs/ha (40 pairs/acre) and assuming a 50% hatch rate, approximately
774,074 advanced fry/ha (313,500/acre) can be produced from a well-managed pond. However,
Huner and Dupree (1984) reported that under normal circumstances about 300,000 fingerlings/ha
(120,000 fingerlings/acre) are produced."
That's with leaving the broodfish in the pond. What would the survival rate be if the broodfish are removed?
That's a good question. The answer is that it will variable. One should expect an average in the neighborhood of 120,000 according to Huner and Dupree. The white paper assumes 311,000/acre of 25 mm (1") BG can be produced. Upon reaching this milestone the standing weight of fingerlings is 139 lbs/acre. Not all that high a standing weight. The paper, if you notice, is not a historical account of production at TWPD. It seems to be more of a set of guidelines seeking to standardize production at the various hatcheries.
They are assuming a 50% hatch rate so I guess the question is really this, how many eggs are they assuming? So at 40 pairs per acre there are 40 females. Earlier they say a female can lay up between 2,000 and 63,000 eggs. Taking an average (32,500) and multiplying that by 40 females ... I get 1,300,000 eggs. At 50% hatch it would seem there are 650,000 fry swimming up. So if a well managed pond produces 313,500 advanced fry per acre then they must be assuming only around 51.8 % mortality. Seems pretty rosy and so I am interpreting that as a lofty goal rather than it being a normal (or average) production number.
As for feeding, I'd start feeding at 8 days like the paper says, not waiting until they get to an advanced growth stage.
I didn't read the paper that way. In it they talk about monitoring the zooplankton population and feeding as needed. When necessary, food is supplemented to fingerlings. They are using two metrics to determine feed rates. One is the growth of samples, the other is the zooplankton population analysis. I don't however think it will hurt to feed the rates in the table as a precaution against problems with the zooplankton populations. I do think taking zooplankton counts is beyond the scope of myself and the OP. I don't want to get that deep in the weeds, LOL.
It is questionable how much the fingerlings are benefitting from feed when the standing weights are below 250 lbs/acre. A fertilized pond can support as much as 550 lbs of BG. Plenty of BG fingerlings have been produced using a combination of organic and inorganic fertilization. The white paper discussed the recipe for a spawning pond to ensure food is available for fry when they hatch. This fertilization and the follow up treatments are absolutely essential for success. There are enough nutrients in the regimen to grow 100,000 BG fingerlings to at least 1.5" in 60 days. The only thing that would prevent that is if the nutrients didn't find their way into zooplankton that the BG could graze on.
