As many of you probably know you all are discussing a very complex topic and one that still needs more research. Lots of variables affect carrying capacity and standing crop.
Standing crop defined as poundage of one or all species present in a water body at a specific moment. Standing crop can be quite variable in the same water body.
For example, Standing crop of all fish in Ridge Lk in IL was measured 9 times in 27 yrs. LMB and bgill dominated the fish community. After each census all bass of useful size for angling were returned and bgill numbers were reduced to usu. 200 per acre of the larger individuals. A small feeder stream allowed a few bullheads, g.sunfish, and minnows to enter the lake. Total weight of fish per acre at each census showed:
Yr... Tot.Wt/ac
1943 = 48.7
1945 = 72.3
1947 = 256.3
1949 = 140.2
1951 = 163.8
1953a= 116.9
1956a= 199.6
1959 = 247.4
1963 = 240.9
a = Drawdowns were used to estimate impact on fishery. Source Mgmt of Lakes&Ponds, by Bennett
Highly variable results from this long term study which indicates to me that none of this stuff is real dependable or our "rules" or guidelines are probably not "definate" and much still needs to be researched and learned about management of the aquatic system.
