sprkplug, There are 2 ways to look at a trophy BG fishery....Tilapia are indeed pellet hogs, yet convert the pellets at roughly a 1.2:1 rate where BG convert around 4:1....If larger BG eat tilapia, you may gain more bang for your buck on tilapia being foraged over the pellets, but BG would probably expend more calories eating live food.
The second view is that with the increased caryying capacity, your pond could theoretically carry twice the trophies with more total available forage along with more, larger, over-abundant LMB to still control the excess BG recruitment.
As for affecting the biomass, tilapia do..they increase it as much as 5 fold in fish, but offset by the larger amount of biomass they consumed to grow, much of it detritus, which often comsumes more oxygen than the Tilapia will...plus as said above, the Tilapia will bring oxgenated water to areas it never existed....in an already aerated pond, the additional oxygen is a moot point.
Tilapia simply allow a pond to find a new, higher carrying capacity by consuming available nutrient other species cannot digest and utilize, moving it into the food chain for the"normal" fish to consume.
There is no succinct way to state all the interactions.
