First, a quick note on the sizes: Before they were flushed into the pond, they showed me a sample and I didn't see any that appeared to be in the 4-5 inch range. I may be wrong, but they appeared to me to be closer to 2-3 inches max. Of course, I could very well just be awful at eyeballing sizes. When you asked about the 1-3 inch bluegill population right now, what I was referring to were the combination of: 2-3 inch BG that were stocked (I am sure there are also a few YOY in there as well) as well as the several schools of small bluegill that hatched in summer. As far as November of last year, I am sure you are correct, but I don't really know because I didn't closely watch the pond the way I am doing now.
This definitely changes things if they were stocked 2-3". That's forage to be consumed by 8-13" LMB. Just a little tip. My longest finger is 3.5", the width of my hand at it widest is 4", the last two segments of my longest finger is 2.25", and the length of my hand is 7". Not exact, but without measurement tools ... it is a decent way to eyeball a length with referenced lengths. So yes, the early November observations may be largely composed of BG you supplemented. Would have been great if you had taken a census before stocking them (for example seines or traps). Relating those catch per unit efforts to surveys following your supplementation could give one an estimate of how well the BG YOY recruited. This supplementation will not be entirely eaten by your LMB. The BG are not so numerous that they cannot outpace the the growth of LMB on a relative weight basis. Some of them are going to escape predation by the LMB and contribute as spawners next year. If only 200-300/acre make it ... it would be ideal IMHO.
Focus is definitely a healthy LMB population. One note that I didn't mention before: I began providing supplemental pellet feed for the bluegill starting in June through October. Will resume this in March next year.
OK. Also important. This will expand your forage potential and greatly benefit BG >5" in length. So the scenario above in the spreadsheet, consider it supported by fertilization and the large BG supported by feed. First pass ... on an annual basis ... 3.6 LB of one popular brand of high quality feed (not to be named) will support 1 lbs of adult BG. There is a fertilizaton effect also. I'll not suggest what it would be in your pond because you already fertilize. Blooms become self shading and the effect from increasing bloom are diminishing. IOWs halving the secchi disc will not double the production. To optimize the contribution of your large BG that will be supported by feed, it would be wise to limit the number of your "Too big to eat" population of BG to a number that they can grow near their maximum potential. I would say 80% of potential because over winter you will stop feeding and they will decline in weight. If you limit the fed fish to this number, you could grow a few BG > 2 lbs. Under fertilization alone this could never be done because the largest BG would be competing for small natural foods under intense competition from smaller fish ... here assuming ... there is a consumable population of BG like the one in the spreadsheet above. When you feed, you should also harvest and manage the number of BG that are not consumable. This should balance with the first pass support the feed is providing these large fish. If you don't, the standing weight of non-consumable fish will increase over time. To the extent their support is not provided by the feed, they will compete with consumable fish and lower the consumption of BG by your LMB. Bottom line, for a given number of LMB, this will lower their potential weights and growth. IOWs, let fertility grow your consumable fish and limit your non-consumable fish to feed. Personally, I would not feed a feed that is small enough for consumable BG to eat. I want a pellet size that the big BG can eat to the exclusion of their smaller sized competitors.
One final question: At this point, would you recommend ceasing to cull anymore LMB at this time? There are definitely more adult bass present in the pond even though I have culled 300+. I have already met the lb goal for culling my advisor gave me in May, but was just continuing on. On Saturday I managed to catch 3 adults and culled them. I thought about possibly holding off on culling any more bass until the Spring, but I am paranoid about wasting all of those bluegill. Sounds to me like you think that would not be a concern?
The population of LMB is always a concern. I would never be unconcerned about that. One of the ways you can relieve concern is to choose which fish are allowed to grow out. This is done through a process of selection and controlling recruited >12" LMB. Applying an expected mortality, then one limits annual recruitment such that the adult LMB population is limited to the desired number. To maximize trophy potential, all selected recruits would be female. Males will lower growth and may contribute to greater LMB recruitment ... and both with lower average adult weights.
My biggest concern is the demographics of your LMB population. Averaging only 1/4 lbs in May ... I am imagining a population of middle aged fish that have lost their early years of growth. Personally, I would not want ... nor recommend ... selecting recruits for growout from this population. If all you were trying to do was achieve balance ... yes ... in that case I would but wouldn't want a selected fish from your current population dieing in 2 or 3 years. I would want some young 12-14" LMB sexed female for the selected group. Personally, I would pay what it takes to get them. These will have the most potential and given the backdrop of investments made ... it seems to me to be an essential piece. There are some distinct advantages to growing out selected fish. To me, selected means they are marked (eg a finclip identify the year of selection) and preferably identified (eg PIT or Dorsal spine clips). Identity allows you to monitor individual growth ... while selection allows you to estimate populations when sampling (eg creel or electro-surveys). It just gives you more tools. It also give you the confidence you need to remove fish. You know, for example, if it isn't marked that it must not be returned to the water. When electrosurveys are done ... these marked fish are returned (unless significantly underperforming) and only unmarked fish are retained. An estimate of population can be done from the results of the survey.
It took years to get in the condition the pond was in before starting your journey. This means it will take a 5-8 years to correct. Possession is 9/10 of the law. If you look at the original outlay of forage above you will see that recruitment of YOY is single most important thing controlling that outlay. The second is the LMB population which is large in size but small in number. What comes first is the food. In other words, the most critical piece is the recruitment of YOY BG. You need to make sure there are high numbers of consumable forage that is only consumable by LMB. If you can budget a forage pond, you can ensure that this variable is not left to chance. 9/10 of the law. The greater the proportion of the forage potential occupied by consumable and consumed BG ... the greater that LMB support can be and the larger they can be.
One important variable that can mess things up is too much survival of BG to non-consumable sizes. Trust me on this. BG grow fast when competition is low and they can easily attain lengths/weights that are either difficult or impossible to consume (considering normal rates of LMB growth). IOWs LMB can not outpace BG in growth when the BG numbers are too low. This lowers consumption, reduces potential for gain, and reduces the biomass of LMB supported. In my example above, the average relative weight of consumed prey is 0.78% the weight of the average LMB. As a rule of thumb, I use 0.91% as the ideal relative weight when the numbers of prey are contrained equal. I want the average to be below that number. What that number is, is the relative weight at which consumption per pursuit is maximized (taking into account the weight of the prey and the probability of successful pursuit). This minimizes the number of pursuits required to consume an arbitrary weight of consumption. Likewise, because pursuits are proportional to population density ... to consume an arbitrary weight of prey ... the population required is minimized when the proportional weight of prey is ~0.91%.
OK, now that said, I still want the average size of consumed prey to be below that number. This because even though the optimum proportional weight is optimum for a fixed population ... the rate of consumption by LMB is not.
Now this is important. If we examine what produces the greatest daily rate of consumption at an arbitrary biomass of prey ... the smaller the prey the better until the probability of successful pursuit approaches 100%. So it is better to have 400 lbs/acre of consumable prey averaging 0.5% proportional weight than it is to have 400 lbs/acre of consumable prey averaging 2%. Here is why. There are 4 times as many prey fish and they will provide 4 times as many pursuits. Furthermore, they will be more successful at consuming 0.5% prey than 2% prey. When one does the math. It take less time foraging to feed to satiation with 0.5% prey than with 2% prey. There is probably a limit to the benefit of smaller prey under the equal biomass constraint ... I think this is were the probability of prey surviving pursuit approaches 0%. The greatest growth experienced by LMB will always be when prey are easily consumed and are high in number. It will never be with BG restricted to 1/4 to 1/3 lengths.
The only way to keep fast growing BG at easily consumable lengths (into years 1,2,3,& 4) is to maintain populations of consumable BG at numbers that prevent them from growing at their potential. One has to overwhelm at the 0-year enough BG YOY recruits so that growth is slow for all consumable BG. This maximizes consumption for LMB populations that are small in number but large in average size. If one fails to recruit/supplement sufficient numbers of 0-year BG ... he will fail to support a population of LMB of high average weight. If he fails to keep the LMB population adequately limited, then he may fail to recruit/supplement sufficient numbers of 0-year BG. So the solution is two fold, which something you already know and are working to implement. But if one succeeds at the first ... it eventually makes doing the second much easier. LMB YOY recruitment is reduced by populous BG and so success of BG YOY recruitment will over time make it easier to control LMB numbers.