Boondoggle,
In year 3 and 4 is where one would begin to get some return on them. But to get most bang for your buck you will need examples of LMB throughout the spectrum of lengths > 20". By this I mean that if the lengths of fish are not concentrated in a small range, you can benefit from growing RBT in situ to the sizes optimum for the lunkers in the pond. We are able goose a pond for fast initial growth. We do this by giving forage fish a head start and by stocking lower numbers of LMB after the forage is established. But that is all that is. It is a goose that will exceed expectations in the early going but it will become increasingly difficult to maintain over time. You correctly intuited the first thing I wanted to convey. Its takes time for LMB to grow long.
There were a few of other things I hoped you would also gain from my post which admittedly requires a lot of reading between the many (so sorry Theo
) lines.
1. RBT aren't the only way to grow big fish. Most of the metabolic demand is in the warm months and forage production is critical during this period. I mention planning to use TP but one could use BG instead. Stocking forage is one of the better ways to keep big fish growing. This is why a small forage pond can help so much. The survival of BG to 2" is relatively low in a pond that has a large standing weight of BG and LMB predators.
This and competition from LMB recruits is what stunts fish to lengths below 20". If you cannot get enough 2" BG recruited in years 3 and later then growing the longer lengths of LMB may be very difficult.
2. The production of 3.5" to 6" prey fish are going to be the determining factor for supporting fish larger than 20". It takes time to grow to that length and their numbers will be much smaller than 2" prey fish. So it is important that the population of LMB reflects the diminishing number of prey fish as they grow in length. IMHO, one of the mistakes we make is trying to preserve members of the original stocking too long. By removing most of the fish as they approach 20", one puts the odds in favor of growing fish to 24" or greater. This is in essence enforcing the trophic pyramid on the biomass of the LMB population. If I were to try to maintain a large population of >20" LMB then I would be essentially turning the trophic pyramid upside down. This is unbalanced, unsustainable, and costly to maintain in this condition.
So in my example I am trying to establish a population of >20" fish at the density of 1 LMB acre. The density of fish 12"-20" ~ 6.4 per acre. On a biomass metric the goal is ~27 lbs/acre of LMB <20" and ~ 9 lbs per acre of LMB >20" and so the biomass of the two populations is pyramid shaped where 25% of the biomass is > 20". 3. In a pond that has reproducing LMB, this plan reflects a subset of the total population. All the figures for forage consumed to support this segment of the total population are valid for a Tulsa location. So in a pond where there are more members of the population, this plan reflects the condition we are trying to get the pond into while understanding that the forage production required will exceed this number.
You will notice that this scenario only allows for annual recruitment of 1.6 LMB per acre into the >12" class. These recruits should only be female fish that you have caught before or stocked yearly of line descended from selection of high vulnerability to angling. If you would tag or fin clip these recruits, then what remains is the relentless harvest of fish > 12" that are unmarked ... all of them ... as many as you can harvest regardless of size or condition.
Each LMB harvested frees 500 or so BG to feed one of your recruits. Supplement forage to feed the recruits which will require stocking them at sizes that reduce their consumption by <12" LMB. Stocking at lengths of 2.4" will eliminate 85% of the probability that they will be consumed by 12" LMB. 2.4" BG grow fast enough that they are not in the consumption window of 12" LMB for very long. If you have 7.4 LMB per acre selected, and other LMB > 12" have been removed, then 4,352 of the 2.4" BG per acre-year would be sufficient to support the selected LMB recruits. Some would be produced by the pond and you could supplement the rest. Note the need for supplemental BG or other equivalent forage stocking. How fast your fish are growing and RW will tell you whether they would benefit from additional forage or not.
