As applied to this discussion at certain times and sizes BG compete with Tilapia for food but at others they do not.
From what I have read TP become less dependent upon zooplankton as they age and this type of feeding behavior is limited to fry 1" or less in length. Even so, fry are capable of converting phytoplankton and detritus and do not solely depend on zooplankton the way that BG do. TP occupy a lower trophic status than BG and even a lower trophic status than some minnows. TP compete for food with organisms that BG eat and this is quite important to the BG part of the equation in a multispecies interaction.
Depending on size structure tilapia often reduce the pressure of predation on BG and allow them to live longer thus reach larger size. This helps larger LMB but lets the BG get to big for small LMB. If you are feeding and food is not an issue for tilapia or BG then all will get bigger quicker and avoid small LMB predation. Thus you will have more and larger better conditioned BG going into winter. This will change over time as the larger and better condition BG have lots more babies the next spring.
This is theory but I have yet to find any scientific support of it. I am not saying it doesn't exist so if you can point us to studies which provide evidence of this I would be most grateful.
I don't want to be argumentative but I really do think there needs to be research to validate these ideas . Here is a possible hole in the theory ...
If BG are not consumed at a smaller size wouldn't more of them survive causing them to stunt, over populate, and be in poor condition?
Are there any studies that indicate that BG numbers, growth, and relative weight, and standing weight increase when TP are added? I've looked for them but just can't find any studies which have determined these benefits and put numbers on these parameters. I wish Swingle had reported the LMB - BG - TP interaction but as far as I can tell he used TP in place of BG when TP were evaluated with LMB.
Based on what I have read from anecdotal evidence it would seem that BG growth is good in the presence of TP but there are no controls. Are BG getting fed artificially and the BG reproduction and numbers inhibited? These are unanswered questions I think. The best test of the interaction would be treatments designed to measure reproduction, growth, and standing weights of BG in the presence of TP and LMB. Here the standing weights of LMB and BG would be same in the controls as in the treatment with TP. Whatever fertility or feed additions should be identical between test and control and the evaluations should be made prior to TP dieoff and subsequent to dieoff in order to understand how the recycling of their biomass may effect LMB and BG growth and condition.
