Update. So far we have removed 1300 BC and BG this spring. And added 12 bass. The bass were 13.5", 2 14", 5 15 ", 2 16", 17" and 18".
My hope is that some the weight removed from the crappie and BG (around 225 lbs) will be put on the bass added to the pond by them eating 3 to 5 inch fish. Hopefully this leaves more room and forage for the remaining 8" BC and 6" BG that are left. Hopefully this allows them to reach a decent harvesting size. We shall see. We are looking at adding a few more bass yet.
The 18 inch bass added weighed 2lbs 7 oz. This seemed a little light? But it is early post spawn yet.
The 18" LMB was probably standard weight pre-spawn.
OK. So based on these numbers and those that you posted in the other thread we have the beginnings of a fall forecast. Lets work the assumption that the weight harvested with be replaced through growth of the existing population. Truth be told, it should be greater than that and it is very likely that last fall's standing weight was greater than this spring's. Even so, there will be recruitment and so with a little luck the existing fish get the harvest gain and the recruits get the fall minus spring gain.
Lets convert the harvest to acres (where the gross acreage = 1.3)
225 lbs / 1.3 = 173 lbs per acre
60% BG = 103 lbs BG/acre
40% BC = 69 lbs BC/acre
Given you are in fertile farm country lets assume 500 lbs/acre for carrying capacity. This could be high or low but it is reasonable for an older bow in northern MO or southern IA. To be sure, the standing weight for LMB will probably sustainably max at 100 lbs/acre but the standing weight may be much smaller as a legacy of the fish kill earlier experienced. The 8" crappie are helping with the BG predation and so many of your BG are big enough to harvest(though smaller than you would like to have to harvest them). You should keep this in mind because at this point harvesting BC without increasing the LMB could remove some much needed BG predation.
So I think it is useful to attempt to gain a sense of what percentage of weight you harvest from each species. In the case of BC, I think you harvested a remarkable percentage of your existing fish. BC standing weights are typically less than 100 lbs but they can be as high as 170 lbs. I have never seen anything documenting standing weights greater than this though I suppose it is possible albeit unlikely. We will make an estimate and use this as a base line for forecast. Now we are going to be wrong but it is worthwhile anyway. The reason it is worthwhile is because the growth this fall will help us to estimate how much we were wrong
and that will guide us to better numbers. I am going to assume a spring standing weight of 140 lbs BC/acre. If so, you removed half of the crappie! Well done!
Now this leaves 70 lbs of growing space and your remaining BC have the potential to double in weight. To double in weight will take them from 8" to approximately 10". Maybe a little less because they will be filling out too OR maybe a little more because the harvest will help secondary trophic organisms to be more numerous. But 10" is a good base line to look for this fall for your BC. If they exceed, then maybe the carrying capacity is less than I estimated, if they fail to achieve the 10", then maybe the carrying capacity is greater.
Now to the BG. If we assume 500 total weight/acre and that the BOW carried 50 lbs LMB and 140 lbs BC going into spring then the BG carrying capacity is 310 lbs/acre (with BC also present otherwise would be greater). So it looks like you may have harvested 1/3 of the spring standing weight of BG. Again ... Well done! Assuming your present standing weight averages 6" in length you can expect a 50% gain in individual weight and an increase to an average length of 7". What is clear is that there is much more room for you to harvest BG. And so I think you can grow the BG to an average length > than 7" (this year) if you continue harvesting through the summer. I think you could harvest an additional 100 lbs of ~ 6" most of which (weight) will be replaced anyways by Fall. Clearly, in your particular pond, the BC or more easily managed and require less harvest than the BG.
Now this takes us to Fall. Guess what? The harvest isn't over. You could harvest potentially another 90 lbs of BC still having 90 lbs to grow into impressive specimens and another 130 lbs of BG. This would take your pond into winter with 273 lbs BG, 90 lbs BC, and 65 lbs LMB(assumes 50 lbsLMB/acre) . So you would be going into winter with 329 lbs/acre in a pond that can carry 500 lbs/acre. There should be better survival and even some growth through winter under these conditions. Next year, your harvest should be easier to implement and the fish much larger than they have been.
