I would never want to dispute any others experience, obsevations or experience with a fish species. In the interest of providing as much comparative information possible, I've questioned some information to consider and provided some extra.
I agree Mozambique tilapia mature earlier, but only by about a week on the average. In optimal conditions, Moz first spawn at an avearge of 11 weeks of age where Blues spawn at an average 12 weeks of age. There are also many reports and studies that show Moz mature as late as 4-5 months and Blues at 5-6 months as well. One consistant comparison I have noticed in the many reports I have read that clearly compare the 2 species is that Moz mature at a minimum size of 14cm and Blues at 10cm.
With all the inconsistancy in cited scientific studies, fact sheets, articles and reports, how can any layman know which ones are accurate.....or even CLOSE to accurate in many cases?
As an example since Dr. Lock was mentioned, Dr. Lock states in this
Paper "Tilapia directly feed on phytoplankton and reproduce every 6 to 8 weeks beginning
when they are 8 to 12 weeks old, depending on species. The T. mossambica and/or T. zilli are probably the best forage
producers, but T. nilotica and T. aurea are excellent.".
Now just to highlight the improper generalities that confuse people terribly and are often made in reports and even worse in studies, Dr Lock says spawning occurs at "10-12 weeks" old. Now I know from research this statement ONLY refers to T. mossambica and T. aurea, because on average, T. zillii reach maturity at 104 weeks (2 years) and T. nilotica at 26 weeks.---I don't see how his stated range is anywhere near accurate average of his four stated species. I am not questioning his knowledge, merely pointing out how easily flawed information can be when not presented clearly for people researching the fish to make an informed decision.
Given the closeness of maturity between Moz and Blues, I would agree that in the same time frame and conditions, Moz would produce more fish due to the early maturity. However, without going in to the brain exploding math required, IMO Blue tilapia will produce more total forage in a
growing season in the same climates and without predation.
Further, and most importantly IMO, is that Moz become lethargic at a temperature where LMB metabolism is higher and the higher metabolism prevents as many lipids (fat) from being stored as compared to the LMB's metabolism when the Blues become lethargic and are gorged upon. This single fact will reduce winter weight loss, increase energy stores and increase the overall health and condition of LMB in the following spring. Actual flesh created from the tilapia's consumed should be nearly identical, but I am unaware of any study that would actually verify the flesh comparison.
It can also be reasonably debated that Blue tilapia will consume a wider variety of material than other tilapia since many user want them for far more plant control than mainly algae.
It does come down to the math, but to reach a desired goal, there is far more to put into the equation than price in what will reach the desired goal. If it is simply a matter of the outright price per pound, Blues won't be a good choice.
Given the considerably better cold tolerance of the Blue, I can't see how any other tilapia can out produce the Blue in sheer numbers and nutrients consumed in a single growing season, but I could be wrong.
FWIW, as I stated, I based this particular stocking rate suggestion overly high to attain the stated goals in a single season. Future stockings would be much lower once the goals are reached.
