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JPS, Are there rule-of-thumb charts for carrying capacities/standing weights? (I'm still unsure of the difference...standing wt = current pounds per acre? carrying cap = a standing weight at which a fish kill is near given current conditions?).


If only it were that simple. What determines carrying capacity is the most adverse conditions. Depending on the year, it could be in the fall during turnover, or it could be brutal snow covered winters. It could be the amount of forage the BOW can produce (a food limitation). An increase in primary production provides not only food for carrying capacity but also additional DO as well, however, the nightly dips are more extreme and so there is a limit. Eventually an aquaculturist must aerate to keep DO at acceptable level as standing weights rise. Things can be going along well and then there are 4 cloudy days in a row in early October. You get the point here. It is that event that determines the carrying capacity. With aeration and feeding you have expanded the standing weight beyond what would be safe for a BOW without aeration.

In ponds with natural fertility and no feed input one can expect that the limitation is most often food, especially in in a yound BOW. I would estimate that your bow would support the maintenance of between 250 and 500 lbs per acre without feed inputs. I base that on averages that your State published in a pond guide that I once read and your location. As ponds age they collect nutrients and they progress toward greater carrying capacity. Carrying capacity depends in part on the type of fish you have. BH can attain higher standing weights than BG would in the same water. The mix of fish matters. The standing weight potential of only BG is greater than when BG are in combination with LMB. This is why BG might DO crash in a forage pond if you don't seine them out.

Standing weight ... its just what your fish weigh ... Hopefully enough description has been provided that it makes sense that a pond may have a standing weight greater than it can carry. These standing weights occur when conditions are favorable and the carrying capacity standing weights occur when conditions are less favorable and as part of the annual cycle of growth and consumption.


Last edited by jpsdad; 09/26/19 06:30 PM.