Okay, for all you "long hairs" out there, I made some rough calculations based on assumptions that show the numbers of Tilapia fry per acre produced for forage consumption is at least 2 billion and much more likely upwards of 27 billion in our East Texas climate.
Here's how I arrived at those very conservative numbers:
From SRAC, Tilapia spawn numbers are 2 to 4 eggs per gram of weight. Assuming the middle number of eggs become fry (3 eggs), assuming a female surviving stocking rate of 5 pounds per acre, this equates to 6811 fry per acre. Assuming those females, let�s call them first generation, all spawn four times (very reasonable) equates to 27244 fry. You also have to factor in weight gains of the females, which means more eggs and more fry. For this, I�m going to very conservatively estimate a four-fold weight gain. Hence, the original, first generation fish will result in about 109,000 fry total per acre�but as we will see, this is miniscule in comparison to the multiplying effects of succeeding generations.
The final result we are after is how many fry per acre result from an initial "surviving" stocking rate of 10 pounds per acre (half of which are assumed to be female). Now this is where it starts to get interesting�. in order to establish a range on the final result, assume that 60% to 90% of the fry are eaten by predators before they can reproduce themselves. The first 6811 fry, then will result in 2724 to 681 survivors and assuming 50% females 1362 to 340 Tilapia that will be reproducers. Let�s call them second generation. The second generation will spawn three times beginning when they are about 3 ounces in weight producing 4,170,168 to 1,041,012 fry. Likewise, assuming the third generation spawns twice which results in 212.8 million to 13.2 million fry. Now further assume the fourth generation spawns once resulting in 27 billion to 1.7 billion fry per acre available for forage�add in, if you want, the other generations but they are actually masked by the last spawn.
It should be obvious, even in spite of math errors and/or differing assumptions that Tilapia reproduction is stupendous and that by the end of the season, the amount of forage that is being generated per acre is flat awesome.
