I am not sure what is meant by the comment of ...."what Dave, esshup, Bill, Bob, or ewest thinks is consumable."
To be sure, it's not meant to offend anyone. There seems to be uniform agreement that 1/4 to 1/3 length BG are most appropriate, most advantageous and/or most needed to maximize the growth of LMB. My intent is to say I dissent from this widely held opinion. One that is frequently promoted by those with considerably more influence here than I. Most often, I do not reply, dissent, or challenge when this idea is republished here. What makes this case different, is that I am trying to help the OP and I do not want my idea of most appropriate, most advantageous, and/or most needed to be confused with the widely held opinion.
Part of what was snipped was further explanation. Very often, people express the opinion that the forage situation in their pond is very good but then follow that with comments of low RW and slow growth. We can have the wrong opinion about the availability of consumable forage. When RW is low and growth is slow ... most often ... there isn't enough consumable forage. When this occurs and we think there is lots of forage to consume, we should review ourselves. We should seek to understand why our opinion is not consistent with the evidence.
To provide an example of a case where the opinion of what is consumable is clearly incorrect ... read
this paper which is the first documented test of the use of formulated feed in a sport fishery (that I am aware). The paper documented effects of feeding. There was a control, a test pond that was drained along with the control for comparisons (after 19 months), and finally a sport fishery that was exploited over the course of 4 years.
Although, the paper documents the substantial increase of potential in support of the forage species (BG), there were some disappointments. For example, the test pond that was drained after 19 months ... it only had 29.4 % higher standing weight of LMB than the control which wasn't even fertilized in the prior 12 months. It is a great example that greatly expanding the forage potential will not necessarily proportionately expand the standing weight of LMB. To be sure, the LMB had the potential to grow much more than they did. The reason they didn't, was because they did not consume enough BG to grow at their potential. I will be first to note that it was NOT the fault of feed that the LMB did not reach greater proportions of their potential. The balance of predator and prey (particular the size of the predators at the time of stocking -- should have been larger) could have been better. But this does deal with the appropriateness of relative sized prey. Much of YOY produced quickly outgrew the capacity of the LMB to consume them.
So the success of feeding in terms of supporting greater weights of the forage species is not in question. However, the idea that supporting greater standing weights of forage fish must lead to proportionately greater consumption of the forage species by LMB .... well that is. This experiment is evidence of that.
Now on to the sportfishery. The sportfishery finally failed and reached a point of considerable imbalance. The pond appeared to be in balance for the first couple of years -- meeting Swingle's definition of balance. But ultimately, the project failed miserably in comparison to Alabama state owned lakes with regard to the LMB. The exploitation of LMB was significantly less in the fisheries test pond only being a minor fraction (69%) of the state owned lakes. This despite the remarkable standing weight of BG carried in the test pond and good gross production of BG. Presumably, LMB carry and exploitation should be proportional to the water's ability to support the forage species. This is an example where that presumption is false. But again, it was NOT the feed's fault, it was that the production of BG that the LMB could consume was lacking (But again, this does deal with the appropriateness of relative sized prey and their abundance).
At draining, they assembled the balance statistics for the fisheries pond. Forage comprised almost 97% of the biomass ... where LMB comprised only 3%. What was remarkable to me was the reported Y/C. This is the ratio of the biomass of consumable prey to the biomass of LMB. In 1964, it was widely agreed that BG between the sizes of 1/4 and 1/3 proportionate length were consumable, important and advantageous prey for LMB. So my impression is that they counted all prey less than 1/3 length of the average LMB (~13" LMB) in this accounting of Y/C.
But here is the rub. Y/C is not just a metric. It incorporates opinion. First, one has to go out on the limb to define "what consumable is and means". Once he has done that ... all metrics he gathers pertaining to Y/C is tainted by his definition which ... without corroborating research ... is simply an opinion. IOWs, when based on an opinion of what defines consumable, reports of Y/C are not objective but rather subjective, subject to a definition that may not have basis in fact. In this paper, they report a Y/C of 8.0. That's a massively high number that suggests that the LMB were swimming in consumable forage. In the context of LMB growth in the test pond it just doesn't make any sense. If it were really that high, the growth of LMB and the average weights of LMB would have been much higher. There is an incorrect definition of "what consumable is and means" at the heart of the disagreement. They were counting forage fish as consumable when they really were not all that consumable free chase in the fishery pond.
Alot of people will read a paper like this and just take what they want from it. They may take, for example, that a fed pond produces larger BG relative to a pond that wasn't fed. I noticed that but I also notice things like E-LMBs of 3% and Y/Cs of 8. I notice how inconsistent those metrics are. I noticed that the test was a failure for LMB. I can't help but notice things like that ... in addition to the greater standing weights of BG and better early growth. I don't just take what I want from it ... I take it all in ... and I try to put all of it into an understandable representation of basic but indisputable principles. For example, principles based on energy balance and how these limit standing weights and the production of consumable/consumed forage. That's what I have been sharing in this thread and the must-read thread. I mean to improve our understanding of these things ... that is my only intention.
I hope ... that all read this post thoroughly ... so that they may understand why I can't agree with the idea that 1/4 to 1/3 sized BG are most appropriate, most advantageous or most needed. I believe otherwise because of a substantial volume of studies (many of which I have already posted here) that do not support that idea. The reason I share my dissent? Because I think it can help everyone make better decisions that result in better outcomes. It's not a shortcoming to be wrong about something one has been taught. It's a strength to question ideas and to be persuaded by good arguments and supporting evidence. Sometimes this requires abandoning an idea that one once believed. This isn't a shortcoming in the least. It takes strength to recognize when one has believed an incorrect idea and to change his mind. All anyone can expect of others is to have good intentions and to do their best in terms serving their interests. Part of that is learning to improve what that best effort can be. Knowledge never sits still. Scientific research is always testing the status quo skeptically. This is how we improve.
