jpsdad, thank you for the article, it was a good read. Here's some detail on the pond's carp population. Since acquired ~4.5 yrs ago, 13 carp have been removed with an average weight of ~15 lbs/carp, a total of ~195 lbs of carp. The ponds surface are is 1.06 acres (Google Maps), This puts the original carp loading of the pond at 184 lbs./acre, which is near the concentration target you mentioned. At this carp loading the pond was very turbid and the fishery was fair at best. This may also be a function of the previous owners management practices or lack thereof. Moreover, if the ponds fish carrying capacity (pre-pellet feeding) was ~500 lbs. fish/acre, 40% of the biomass was carp. The reason I started removing carp count was my belief that 1) lowering the turbidity would help the LMB and BG and 2) the carp were probably eating A LOT of bottom dwelling bugs that would now be available to the BG.

Now getting more into the details, the 13 carp were primarily removed in two fishing seasons, 2019 (8) and 2022 (5). The pond turbidity before 2022 was improved, but still cloudy with suspended solids (could see down ~2-3 feet on GOOD day, usually <2'. The fish population was greatly improved through a combination of pellet feeding, selective culling, and re-stocking. I'm unable to quantitatively relate the removal of the 8 carp to the improvement in the fish population given all the changes being made at the same time (the pond as purchased was a train wreck in need of dramatic changes). The remaining 5 carp were removed between July - October last year. Every time a carp was removed, the water clarity improved.

It wasn't until this year that the weeds exploded with the clear water and my new learning that the available phosphorous would be used by the aquatic vegetation and not necessarily by phytoplankton (other than early spring) to produce more zooplankton. I cannot tell any difference in the fish population from last fall, when all the carp were finally removed, until now.

This begs the question of what to do next. I'm not yet sold on releasing common carp or a grass carp or two back into the pond given the effort required to fish them out. Plus, even a few of them may comprise 10-20% of the fish biomass. In addition, the article noted that in large lakes, common carp biomass is often negatively related to the abundance of other fish, especially BG and LMB. The most important reason may be habitat degradation by common carp, which increases the turbidity of the water in the lake through its benthic foraging behavior, switching lakes from the clear- to the turbid-water state (Stewart & Downing Citation2008). I recognize that my pond isn't a large lake, but the principle is the same. Using the carp to add turbidity will decrease light penetration and weeds. They may also improve the zooplankton population, but I don't know by how much and to what degree this would help LMB/BG fry grow bigger faster.

Not sure this info helps, as I'm still undecided on the path forward. Just wanted to share the background detail and current conundrum.