Gosh this thread is sprinting! I've been busy...but will take some time to address a few issues.
I believe that HSB-Tilapia ponds could be very productive but success depends on several factors.
1. HSB size structure: Since HSB have relatively small mouths reative to their body size, I am of the opinion that tilapia fry COULD grow fast enough to find themselves safe from predation in short time in presence of small HSBs. Optimum HSB size may have to be 2#+ to make tilapia forage work consistently.
2. HSB population: I wouldn't expect success in situations where HSB population was more than 100/acre without supplemental feeding.
3. Tilapia food availability: Young tilapia need plankton or algae for fast growth. Fertilizer is recommended....and if you are opposed to inorganic I would recommend organic fertilizers like cottonseed meal to encourage plankton production.
4. Alternative forage: Since HSBs feed during cold months, an alternative food source would be necessary to maintain proper nutritional needs. Bluegill...threadfin shad...minnows.
My experience with HSBs at high density in small shallow farm ponds (3/4 acre and below) has shown that fish will feed in very shallow water as long as DO is at desirable levels.
Tilapia fry and fingerling survival rate in our HSB grow out pond was relatively good when HSBs were say less than 5", but we've seen that tilapia population dwindle since the HSBs grew past that point. Tilapia fry and small fingerlings were extremely abundant through the summer and early fall...streaming down the shoreline with fear in their eyes. We slowed the artificial feeding program after first cold front in October. At that time our max HSB size was 10", after being stocked at a 2" size in late June. Harvest with seine 2 weeks ago revealed a few HSBs over 12". Keep in mind we stocked HSBs at a rate of 10000/acre for fingerling production.
There has been some discussion addressing bluegill and redear population and size increase associated with tilapia. We have learned for a fact that perch will eat large numbers of tilapia fry.
Results of our fall surveys reveal that tilapia don't appear to have any negative impact on bluegill/redear population size, just some very happy LMBs.
