Thank you TJ.
Expending a considerable amount of time yesterday searching for a web copy of Don's paper, I found that the web document Dave Willis co-authored had inspired a previous thread here at pond boss that was initiated by snrub. Like me, he also found Don's findings remarkable. That thread basically dealt with the question of whether snail forage significantly limited the biomass of RES and whether focusing on the production of RES was a doable project. In the end, there seemed agreement that RES prefer snails when available but will readily adapt to other available forage allowing them to achieve a respectable biomass. Implicit to this, RES can support a managed predator.
Swingle noted that RES reproduction was insufficient to support good growth of LMB. Many sources report that RES are age 2 at sexually maturity. This contrasts considerably with BG which have under ideal conditions been document to reach sexually maturity at age 0. So I 'think' I agree that LMB would grow slower and achieve lesser ultimate size in bows with RES only as opposed to bows with BG only.
The paper on standing weights (broken link above) did provide some interesting data on the standing weights of LMB in the presence of other species. One might think that LMB standing weights would be a little higher in ponds where BG were present than in ponds where RES were present. I would have almost taken this for granted. But this was not the case in the aggregate of the 42 ponds surveyed. Where RES were present the standing weight of LMB averaged 57 lbs/ac and where BG were present the standing weight of LMB averaged 49 lbs/acre. Looking at their absence provides interesting data as well. When RES were absent, LMB standing weights were 34 lbs/ac. It would seem the presence of RES was associated with an additional 70% in standing weight of LMB. When BG were absent, LMB standing weights were 29 lbs per acre and so the presence of BG was associated with an additional 69% in standing weight of LMB. They seemed to provide roughly equivalent benefits to the standing weights but RES seemed to allow LMB to achieve greater standing weights by about 16%. The data seems to suggest that RES and BG are comparable with regard to the carrying capacity of LMB.
This doesn't mean that RES are better than BG or as good as BG for growing large bass. I have wonder whether in the presence of RES that LMB are greater in number and lesser in individual weight than when in the presence of BG. Perhaps invertebrates are larger percentage of LMB diets in the presence of RES making the LMB more panfish-like in terms of growth. TJ, perhaps you can shed some light on this from your experience.
All this brings us back to question of how when sharing a pond with BG can RES represent the lion's share of the biomass of panfish. I have already mentioned the possibility that the condition is reflective of the initial stocking omitting the introduction of BG. Even if so, if conditions prevailed that were more beneficial to BG, then BG presence should eventually squeeze back RES. It occurs to me that a food chain might benefit RES over BG particularly if the chain was concentrated in large benthic organisms or organisms that prefer low light levels. For example, shredders like crayfish, PK shrimp, and Hyallela Aztec. RES also have first crack at chiromids. So is there a invertebrate forage combination that will favor RES?
In the other
PB Thread , Bill Cody mentioned that the BOWs were 24-28 years old and so it would seem that LMB and RES are a sustainable combination. He mentioned that the RES were 7" to 8.5 " at 7 years and that growth was slow. Even so, given the standing weights of RES, I can only infer two possibilities for the slow growth. The first possibility is that the RES were overly reproductive despite harvesting efforts OR the RES were under harvested. If the latter, it would seem that this is manageable and better growth can be expected when RES are subjected to cropping. Bill, I would greatly appreciate any thoughts you may have on how cropping may increase growth and what may be a sustainable rate of cropping in terms of lbs/acre-year in terms of RES carrying capacity. Given a winter mortality of 30%, I wonder if 30% of standing weight isn't a good idea and might provide the benefit of greater winter survival.
Snrub, I am going to read through your thread on the SMB/RES again as well. Do you have any harvest records and can you comment on RES growth and reproduction in your SMB/RES bow?
